BRITISH, ANTARCTIC EXPEDITION 1907-9
UNDER THE COMMAND OF SIR E. H. SHACKLETON, C.V.O.
REPORTS ON THE SCIENTIFIC INVESTIGATIONS
GEOLOGY
VOL. II
CONTRIBUTIONS
TO THE
PALM ONTOLOGY AND PETROLOGY
OF
SOUTH VICTORIA LAND
BY
W. N. BENSON, B.Sc. ; F. CHAPMAN, A.L.S., F.R.M.S.; Miss F. COHEN, B.A., B.Sc. ;
L. A. COTTON, B.A., B.Sc. ; C. HEDLEY, F.L:S. ;
H. I. JENSEN, D.Sc.; D. MAWSON, D.Sc., B.E. ;
Pror. E. W. SKEATS, D.Sc. ; J. ALLAN THOMSON, M.A., D.Sc. ;
A. B. WALKOM, B.Sc.; Pror. W. G. WOOLNOUGH, D.Sc.
WITH 38 PLATES AND 18 FIGURES IN THE TEXT
ALSO
INDEX TO VOLUMES I & I
7 LONDON
PUBLISHED FOR THE EXPEDITION BY WILLIAM HEINEMANN
21 BEDFORD STREET, W.C.
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NATURAL HISTORY
BRITISH ANTARCTIC EXPEDITION 1907-9
UNDER THE COMMAND OF SIR E. H. SHACKLETON, C.V.O.
REPORTS ON THE SCIENTIFIC INVESTIGATIONS
GEOLOGY
PUBLICATIONS OF THE BRITISH ANTARCTIC EXPEDI-
TION, 1907-9, UNDER THE LEADERSHIP OF SIR E. H.
SHACKLETON, C.V.O.
REPORTS ON THE SCIENTIFIC INVESTIGATIONS
(Published for the Expedition by William Heinemann, London)
BIOLOGY
Vol. I, Part I. On Collecting at Cape Royds. By James Murray, F.R.S.E., F.Z.S. 1s. 6d.
net.
If. On Microscopic Life at Cape Royds. By James Murray, F.R.S.E., F.Z.S.
5s. net.
Ill. Antarctic Rotifera. By James Murray, F.R.S.E., F.Z.S. 5s. net.
IV. Musci. By Jutes Carport. ls. net.
The above four parts also bound in one volume, 12s. 6d. net.
V. Tardigrada. By JAMES Murray. 10s. net.
VI. Rhizopodes @eau douce. By EUGENE PENARD. 3s. net.
VII. Fresh-water Alge. By W. West, F.L.S., and G. 8. West, M.A., D.Sc.,
F.L.S. 3s. net.
Vol. II, Part I. Mollusca. By Cuartes Heptey, F.L.S. 1s. 6d. net.
Il. Antarctic Fishes. By E. R. Wate, F.L.S. 1s. 6d. net.
III. Mallophages. By Professor L. G. NEUMANN. Is. 6d. net.
IV. Astéries, Ophiures, et Echinoides. By R. Koruter. 5s. net.
GEOLOGY
Vol. I. Glaciology, Physiography, Stratigraphy, and Tectonic Geology of South Victoria Land.
By Professor T. W. E. Davin, C.M.G., F.R.S., M.A., Hon. D.Se. (Oxon), and
R. E. Priestey, F.G.S. With Short Notes on Paleontology by T. G. TayLor,
B.A., B.E., B.Se., and Professor E. H. Gopparp, D.Se. Paper boards, £2 2s.
net; also in cloth, £2 12s. 6d. net.
Vol. II. Herewith.
No further publications in this series are contemplated.
PUBLICATIONS IN THE PROCEEDINGS OF LEARNED SOCIETIES
Some Results of the British Antarctic Expedition, 1907-1909.
By Sir E. H. SHackieton, C.V.O. Geog. Journal, vol. xxxiv, November 1909.
The Tidal Observations of the British Antarctic Expedition, 1907-1909.
By Sir Grorce Darwin, K.C.B., F.R.S. Proc. Roy. Soc., 1911.
An Outline of the Geological Results of the British Antarctic Expedition of 1907-1909.
By Professor T. W. E. Davin and R. E. Priestitey. Internat. Geol. Congress, Stock-
holm, 1910.
Antarctica and Some of its Problems.
By Professor T. W. E. Davin. Geog. Journal, vol. xliii, June 1914.
The Auroral Log of the British Antarctic Expedition, 1907-1909.
Edited and discussed by Dr. D. Mawson. Proc. Roy. Soc. South Australia, 1916.
POPULAR NARRATIVES
(Published by William Heinemann, London)
The Heart of the Antarctic.
By Sir E. H. SHaAckLETON, C.V.O. In2 vols. Crown 4to. Illustrations, Maps, and
Portraits, 36s. net. Also an Edition de luxe with special Contributions, vellum,
£10 10s. net. Also a New and Revised Edition with Illustrations in Colour and
Black and White, Crown 8vo, 6s.
Shackleton in the Antarctic.
By Sir E. H. Suackteton, C.V.O. (Hero Readers Series.) Crown 8vo, 1s. 6d.
BRITISH ANTARCTIC EXPEDITION 1907-9
UNDER THE COMMAND OF SIR E. H. SHACKLETON, C.V.O.
REPORTS ON THE SCIENTIFIC INVESTIGATIONS
GEOLOGY
VOL. II
CONTRIBUTIONS
TO THE
PALHONTOLOGY AND PETROLOGY
OF
SOUTH VICTORIA LAND
BY
W. N. BENSON, B.Se.; F. CHAPMAN, A.L.S., F.R.M.S.; Miss F. COHEN, B.A., B.Sc. ;
L. A. COTTON, B.A., B.Sc.; C. HEDLEY, F.L:S.;
H. I. JENSEN, D.Se.; D. MAWSON, D.Sc., B.E.;
Pror. E. W. SKEATS, D.Sc.; J. ALLAN THOMSON, M.A., D.Sc. ;
A. B. WALKOM, B.Sc.; Pror. W. G. WOOLNOUGH, D.Sc.
WITH 38 PLATES AND 18 FIGURES IN THE TEXT
ALSO
INDEX TO VOLUMES I & II
LONDON
PUBLISHED FOR THE EXPEDITION BY WILLIAM HEINEMANN
21 BEDFORD STREET, W.C.
1916
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PRINTED AT THE COMPLETE PRESS
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7
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PREFACE
THE publication of the second volume of the Geology of the British Antarctic Expedition
of 1907-1909 has been considerably delayed through several causes, chief among which
are the departure of Sir Ernest Shackleton on his present Antarctic Expedition and
above all the Great War.
The latter has been such an obsession and has so wholly claimed the active services
of both of us * that it has been found to be quite impossible under the circumstances
to summarise and modify many of the statements in Vol. I. We must therefore be
content with touching on just a few salient points.
First in regard to the Drygalski Ice Barrier Tongue and the Nordenskjold Ice Barrier
Tongue. In the opinion of one of us (Professor David) the sections given on Plate XIV
and the plate facing p. 74 are probably incorrect. Instead of both these glaciers being
shown as riding on an embankment of their own moraines and subglacial gravels, it is
probable that these glaciers are afloat for the greater part of their length, and the
longitudinal section, if generalised, should probably be drawn as follows :
THE DRYGALSKI ICE BARRIER TONGUE.
ROSS SEA
Land Rise
Cili
or
Threshold
This interpretation is suggested (1) by the few soundings around the Drygalski Ice
Barrier which show a depth of 300 fathoms close to the extreme end and 668 fathoms
at 20 miles back, shorewards, from the end of the Barrier ; (2) by the fact that Glacier
Tongue between Hut Point and Cape Evans, a smaller edition of the Drygalski and
Nordenskjold Ice Barrier Tongues, actually broke away during the earlier part of Scott’s
last Expedition ; (3) by many interesting sections published by Professor J. W. Gregory
in his book on Fiords.
Next, the question has been raised by Frank Debenham, B.Sc., one of the Geologists
of Scott’s last Expedition, as to whether along the western side of what we have termed
the Antarctic Horst the marked westerly descent of the rocks is due to flexing or faulting.
On this point we have no definite evidence. i
The photographs with whieh Vol. I is illustrated are the work of several members
of the Expedition. In the case of many the identity of the photographer has been
* At the eleventh hour this volume was hung up in the press on account of Major (Professor)
T. W. E. David and Captain R. E. Priestley being engaged on military service and too fully occupied
or out of touch with the printer. The undersigned is engaged in war service in England, and
has arranged to take over the work of passing the volume through the press.—D. Mawson.
v
vi PREFACE
lost, so that we are unable to mention his name in connection with them. In this
matter Mawson * was the largest contributor, supplying forty of those reproduced,
including the telephoto view of Mount Erebus. .
We are particularly indebted to the authors contributing sections forming this second
volume of Geology for their gratuitous and unselfish services in working up the geological
results of our Expedition.
We also wish to express our hearty gratitude to Mr. J. A. Tunnicliffe, of the University
of Sydney Fisher Library Staff, for his care and patience in preparing the Index to
Vol. Lf
The publication of the bibliography of Antarctic Geology prepared by Mr. W. 8.
Dun, intended for this volume, has been postponed at the last moment, as it is now
several years in arrears owing to delay in printing. It is intended that in the near
future it shall be brought up to date and published elsewhere.
Finally, this volume is also indebted to the generosity of the Royal Society, who,
in addition to the £200 grant towards the printing of Vol. I, have now voted a further
£25 to cover the cost of printing the index now appearing.{ .
* As a matter of fact, I believe Professor David contributed a greater number of photographic
illustrations to that volume.—D.M.
+ I have extended Mr. Tunnicliffe’s Index, so that that appearing at the end of this volume
covers both Vols. I and I1.—D.M. q
t All expenses connected with the preparation of matter to form these Geology volumes were
defrayed by Professor David from money raised by him in a series of lectures upon the work of
the Expedition delivered throughout Australia and Tasmania.—D.M.
PART
I.
IDK
III.
LINE
CONTENTS
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES. By D. MAWSON,
D.Sc. \
REPORT ON THE FORAMINIFERA AND OSTRACODA FROM ELEVATED
DEPOSITS ON THE SHORES OF THE OS SEA. By FREDERICK CHAP-
MAN, A.L.S., F.R.M.S al Cosy Prats
REPORT ON THE FORAMINIFERA AND OSTRACODA OUT OF MARINE
MUDS FROM SOUNDINGS IN THE ROSS SEA. By FREDERICK CH: eL AN,
A.L.S., F.R.MS. i. ) - 8b,
REPORT ON A PROBABLE CALCAREOUS ALGA ELST THE CAMBRIAN
LIMESTONE BRECCIA FOUND IN ANTARCTICA AT 85° S. By FREDERICK
CHAPMAN, A.L.S., F.R.M.S r
= )
a | a
. REPORT ON MOLLUSCA FROM ELEVATED MARINE BEDS, “ RAISED
BEACHES,” OF McMURDO SOUND. By CHARLES HEDLEY, F.L.S.
EREBUS, ANTARCTICA. By H. I. JENSEN, D.Sc. 95:1,2(2 \ =
Ww
. REPORT ON THE INCLUSIONS OF THE VOLCANIC ROCKS OF THE ROSS
ARCHIPELAGO. By J. ALLAN THOMSON, M.A., D.Sc., F.G.S.
APPENDIX TO PART VIII: HGIRINE-AUGITE CRYSTALS FROM A
MICROSANIDINITE OUT OF THE TRACHYTE FROM MOUNT CIS, ROSS
ISLAND. By MISS F. COHEN, B.A., B.Sc.
. REPORT ON THE PETROLOGY OF THE DOLERITES COLLECTED BY THE
BRITISH ANTARCTIC EXPEDITION, 1907-1909. By W. N. BENSON, B.Sc.
. REPORT ON THE PYROXENE GRANULITES COLLECTED BY THE BRITISH
ANTARCTIC. EXPEDITION, 1907-1909. By A. B. WALKOM, B.Sc.
. PETROLOGICAL NOTES ON SOME OF THE ERRATICS COLLECTED AT CAPE
ROYDS. By DR. W. G. WOOLNOUGH, D.Sc., F.G.S.
. REPORT ON THE PETROLOGY OF SOME LIMESTONES FROM THE ANT-
ARCTIC. By ERNEST W. SKEATS, D.Se., A.R.C.S., F.G.S.
. PETROLOGY OF ROCK COLLECTIONS FROM THE MAINLAND OF SOUTH
VICTORIA LAND. By D. MAWSON, D.Sc., B.E.
APPENDIX TO PART XIII: PETROLOGICAL DESCRIPTION OF SOME
ROCKS FROM SOUTH VICTORIA LAND. By LEO A. COTTON, B.A., B.Sc.
Vii
PAGE
i)
or
lo 2)
or
. REPORT ON ANTARCTIC SOILS. By H. I. JENSEN, D.Sc. 63.) (26-9) «#89
. REPORT ON THE PETROLOGY OF THE ALKALINE ROCKS OF MOUNT
93
161
CORRIGENDA TO VOLUME I
Page 37, line 8, for Farrar read Ferrar.
122, ,, 7 from foot, for XXXIX read XXXIII.
176, Plate XLIX, figure 2, for Armytage read Mawson.
181, line 19, for Brocklehurst read Mawson.
231, ,, 6 from foot, for Lyothyrina read Liothyrina.
247, ,, 12 from foot, for J. T. Prior read G. T. Prior.
266, ,, 12 from foot, for Blockmann read Blochmann.
285, ., 15, for Reclus read Réclus.
286, ,, 3 from foot, for funf Sudpolar read fiinf Siidpolar.
Pn », 2 from foot, for Sudpolar read Siidpolar.
301, ., 2 from foot, for Pass read Pas.
PART I
A CONTRIBUTION TO THE STUDY
OF ICE-STRUCTURES
(With Seven Plates and Six Figures in the Text)
A BY
D.’ MAWSON, DSc.
University of Adelaide
CONTENTS
MAINTRODUCIORY, = 2 415, 4. =) ee ene ies
Il. THE LAKE-ICES . : : : : : : ; : ‘ : ; 4
1. PRELIMINARY E : ; : : ; : c c : ‘ A
(a) Causes contributing to the Accumulation of Saline Matter in the
Lakelets : : ‘ : : . 4
(6) Reasons for the varying Salinities of the Lakelets . ‘ : ; 4
(c) The Nature of the Saline Accumulations 4
2. GREEN LAkE 5
3. Rounp Lake ; : ; : : : é : : : F 8
4, SHALLOW LAKE 9
5. Biue Lake . : . : : : : : ‘ : : : 10
6. Coast LaxEe 5 ; ; F F : ; : : : : 14
7. CLEAR LAKE é : 3 ; ‘ : : : : : : 15
8. GuactER-IcE (for comparison) 6 : : : : ; ; : 16
9. CLASSIFICATION OF THE CRYSTALLINE TEXTURES OF THE LAKE-IcEs : 16
III. SEA-ICE é : F : : F ; : : : : 5 ; 16
IV. ICE-STALACTITES : : ‘ : : ; : : F : : 17
V. A COMPARATIVE STUDY OF ICE-CRYSTALLISATIONS FROM VAPOUR . 18
(a) Crystallisations from Concentrated Vapour. : : é ; : 19
(b) Crystallisations from Attenuated Vapour. , : ‘ : : ; 19
(c) Crystallisations from Rarefied Vapour. : : : : : 20
VI. EXPLANATION OF THE PLATES : : : ‘ : ; : 23
BRIT. ANTARCT. EXPED. 1907-9. VOL. II. A
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I. INTRODUCTORY
Durine the winter months much time was spent in investigating the composition,
texture, and fabric of the varied ice-forms in the vicinity of Cape Royds.* For this work
a Low-temperature Laboratory was constructed in which the temperature was always
well below freezing-point. Samples could be treated there in much the same way as
other rocks and minerals in an ordinary laboratory. A ready method of studying the
crystalline fabric of the specimens was discovered accidentally and happened in this
way. It was noted that the large blocks of very cold ice brought into the Hut and piled
up in the big melters over the stove quickly became frosted over by the freezing upon
them of vapour rising from the bottom of the pot.
In this way, within a few minutes, all the crystal individuals were differentiated to
the eye, for the frost additions were microscopic plates developed in optical continuity
with the particular individuals upon which they formed. The effect was that every
crystal gave a bright reflection when held at a particular angle.
The method of procedure adopted for the investigations was to bring the specimens
inside in as cold a condition as possible and place them in the colder portions of the com-
paratively moist Hut. After a few minutes, upon moving them about in the light, the
grain structure could be observed with ease, by reason of the diverse scintillations.
On some moonlight occasions in the winter, depositions of the kind, formed naturally
from frost, were observed on the surface ice of the lakes.
With the object of photographing bubbles and other objects contained in the ice,
slabs of a fair thickness were first sawn, then reduced to the required thinness by rubbing
down on a slightly warm plate, tilted at a small angle to carry off the water.
The Buchanan Hydrometer was used for specific gravity determinations of the thaw
water.
For pure water for chemical work freshly fallen snow and some of the névés in the
vicinity were used, and found to be actually purer than the distilled water brought
from New Zealand.
* The study of ice and ice-forms was one of my duties on the British Antarctic Expedition,
1907-1909. On return a short popular note to form an appendix to The Heart of the Antarctic was
forwarded to London on brief notice.
When the Geological Memoir was in preparation by Professor David and Mr. Priestley, I was
to have co-operated at their request, but preparations for the Australasian Antarctic Expedition,
1911-1914, intervened. Vol. I of Geology has now appeared with excellent chapters on Glaciology,
and the notes now submitted are merely fragments in amplification. For several reasons there
has been considerable delay in publication of this matter, which was ready four years ago. Since
then my observations have been much widened, and will appear shortly in the Scientific Results
of the Australasian Antarctic Expedition, 1911-1914.
Regret is to be expressed at the loss in transit between Adelaide and Sydney of a consignment
of brines and eryohydrates brought back for examination; with them was lost some valuable
information.—D.M., December 1915.
4A A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
Il. THE LAKE-ICES
1. PRELIMINARY
Ice from the lakelets received most attention. There are many such small basins
on Cape Royds Peninsula, as will be noted by referring to the sketch of the neighbour-
hood prepared from the plane-table survey of Professor David and Mr, Priestley (see
The Heart of the Antarctic, Vol. I, p. 131).
Much of the interest in the ice from these lakes centres in the fact that the waters
of the lakes illustrate various degrees of salinity and consequently the ice shows con-
siderable range of structure. Some of the lakelets are much salter than others, ranging
from quite fresh-water basins to others as salt as the sea. In the case of the latter,
highly concentrated brine residues are developed in the course of freezing, which them-
selves eventually solidify after arriving at the cryohydric concentration.
(a) Causes contributing to the Accumulation of Saline Matter in the Lakelets.
Three contributing causes are likely to have operated in furnishing the salt.
(i) Salts carried on to the land as spray from the sea during gales in the summer
and saline snow from the floe blown on to the land during the winter.
(ii) Leaching of salts from the upraised marine muds which, it would appear, at one
time covered the whole of the peninsula, and remnants of which are still to be seen.
(iii) Leachings from the alkaline igneous lavas of the neighbourhood.
Without entering into a discussion upon the subject, it will be stated that for obvious
reasons these three agencies must be regarded as contributing in the order stated. The
contribution blown from the sea is sufficient to account for all the salt. In fact it must
actually be held accountable for almost all. The contribution from the third source
must be very small indeed, for the prevailing temperature is too low for active chemical
decomposition.
(b) Reasons for the varying Salinities of the Lakelets.
In order to explain the freshness of some of the basins as opposed to the salinity
of others, it is necessary to draw attention to many agencies which must have been
operative. In the first place, as the winds which carry the saline matter over the land
are from the S. and §.S.E., the extremity of the peninsula must receive most of the
contributions blown from the sea. The neighbourhood of Blue Lake is more in shadow
in this respect, particularly as the head of Back Door Bay is frozen over excepting fo
a very short period of the year. :
The wind distributing the salts over the peninsula is deflected somewhat by the
valleys, and so the contour of the land has some determining effect. A situation near
to the actual Cape itself, where most of the spray dashes over, ensures salinity. The
relative size of the catchment basins and the contained lakelets is important.
The nature of the catchment and its disposition, whether it be rock or snow surface,
and whether it be more or less accessible to the sun is a matter of great importance, for
in all basins where there is much thaw in summer a considerable annual contribution
of saline matter will be brought in with the water. In order that it may become very
saline the lakelet itself must be well contained else an exceptional thaw would be liable to
sweep out the salts already accumulated.
(c) The Nature of the Saline Accumulations.
Besides the salt in the lakelets themselves there is always, in summer-time, much saline
to be observed over a great part of Cape Royds Peninsula in patches beneath, or in the lee
of, stones lying on the surface. In such positions it has the appearance of snow and
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 5
may be passed by as such. In the winter-time projecting stones arrest a quota of the
flying salme snow. As summer approaches, the water from thawing of snow lying about
again freezes as soon as the shadow of the rock is entered. Even in the shadow of
the rock ablation proceeds rapidly and in time only the salt remains. The presence
of the rock acting as a wind-break further protects the accumulation from being carried
off by subsequent gales. The illustration (Plate I, Fig. 2) is a view of a pebbly slope
high up in the Green Lake basin; small patches of white salt can be seen behind many
of the pebbles, easily mistaken for snow.
The saline mineral matter as collected and air-dried contains slightly under fifty
per cent. of water, which is driven off at 100°C. It is a mixture of sulphates and
chlorides of sodium and magnesium with but traces of other substances.
2. GREEN LAKE
For further information refer to Vol. I, p. 148. Green Lake is a shallow lakelet
in a rock basin, receiving the drainage of a relatively large catchment area (Plate I,
Fig. 1). Its mean diameter is about sixty yards; greatest depth slightly more than
six feet, and it is situated some twenty to thirty feet above sea-level. As the water
is unusually briny it thaws readily each summer. The common red-brown alga of
the Cape Royds lakelets flourishes in the fresher waters of the margin, where thaw-
water trickles in from adjacent snow-banks; in the briny central portion there is
nothing living excepting bacteria and perhaps other unicellular organisms. The
bottom of the latter situation is mantled with a layer of black putrefying mud, from
which so much sulphuretted hydrogen is evolved that both the water and the ice
have a most disagreeable odour. The gas is doubtless liberated by the action
of thio-bacteria, which appear to thrive in the imprisoned waters beneath the
surface of the lakelet, existing by reason of their rdle in robbing the sulphates of
their oxygen.
Three shafts were sunk by Priestley * in this lake during the winter. The sections
exposed in each corresponded very closely in detail. A diagrammatic representation
of the July shaft is figured herewith (Fig. 1). In June one foot of brine was found
unfrozen at the bottom of the lake. In July there was practically no brine left; none
at least where that particular shaft was sunk, distant only twelve feet from the former.
On examination at the Hut, the brine found liquid in the shaft sunk in June was
found to contain much sulphate and chloride with a small amount of carbonate
and sulphite. With these acid radicles were combined the following bases in order of
relative abundance: sodium, magnesium, calcium, potassium, and ammonium. There
was present also free sulphuretted hydrogen and carbonaceous matter which charred
on evaporating to dryness.
The brine, on standing in a corner of the Hut for a few hours at a temperature
of about 30° F. (above its freezing-point), developed a distinctly fluorescent capping
layer. From this layer botryoidal masses of a white cloudy substance gradually
extended themselves, growing downwards into the liquid at the rate of about half
aninch a day. This was noted to take place only in open or loosely corked bottles,
and was immediately arrested upon excluding the air. In the course of time the
growth extended throughout the liquid, and later settled as a slimy precipitate which
proved to be chiefly organic matter. There seems to be no doubt but that the growth
was bacterial.
* I wish to record my great indebtedness in widening the scope of these observations on ice-
structures to Mr. R. E. Priestley and all members of the Expedition who assisted him in the winter
programme of sinking shafts through the ice of the lakelets.
6 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
The temperature of the brine when bottled at the lake was 22° F. (necessarily
the temperature of freezing equilibrium for that particular mixture), further reduction
Sp. Gr.
Bee) hrs: Cwater)
ia i y
i i
4%
elol ate
1.00005
Clear ,bubbly, prismatic Ice
in horizontal layers.
1.0007
vr oe a ee ete a
nen it
Al! ‘i I!
i|\
i
MK Hh
1.0014
a
Tra tap arent coarse-prismatic¢
ce.
1.0086
Transparent ice with white
Saline tracts between the
1.0029 Prisms.
1.0045
I .00390
on
oO
1.0309 Highly saline, white
translucent Ice.
Foul Mud.
Rock.
Fic. 1. Diagram illustrating the Ice Section at Green Lake
of the temperature caused a separation of H,O as ice, but there was always a hquid
remainder even at temperatures far below zero Fahrenheit.
Two different samples of the liquid brine from the bottom of this lake have been
examined by Mr. F. B. Guthrie, F.C.S., analyst to the Department of Agriculture,
N.S.W., with the following result :
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 7
SAMPLE 1 2
Organic residue settled to the bottom of the bottles per cent. per cent.
(bacterial ?) : ; : : : ; 0-077 0-089
Water driven off at 100°C. . : F 2 é 87-921
Water and organic matter expelled by ignition : 0-434
Saline residue j : ; é 5 : 3 11-568
Qualitative tests carried out at the Hut, testing the ice chemically at intervals
between the surface and the residual brine, showed the surface fifteen inches to be
almost pure water. Below fifteen inches the saline contents rapidly increased. This
is well illustrated in the column of densities below.
The following is a table of specific gravity determinations, by the Buchanan Hydro-
meter, of waters resulting from melting samples of the ice taken at intervals in the July
shaft. The second column represents determinations of the temperature of commence-
ment of freezing of the thaw-waters.
Specific gravity Commencement
SEE REL at 4°C. of freezing (F.)
Surface to fourinches . : . b . : 1-00005 32
Seven inches to-ten inches : ‘ ; : ; 1-0007 31-95
Twelve inches to fifteen inches ; : ; f 1-0014 31-9
Two feet six inches to three feet 3 ‘i ; S 1-0026 31-75
Three feet to three feet six inches. ‘ ; F 1:0029 31-7
Three feet six inches to four feet P A 2 f 1-0045 31-5
Four feet to five feet , é é , ‘ 1:0090 30-9
Five feet to five feet three inches. ; b F 1:0300 29-8
The liquid brine from the June shaft between five feet six inches and six feet had a
specific gravity of 1-142 at the same temperature ; commencement of freezing 22° F.
A sample of the ice from the very bottom, five feet three inches to five feet six inches, of
the July shaft was taken to the Hut with others and left in the outer laboratory pending
examination. Unfortunately it was contained merely in a bag, as was the usual procedure.
When examined it was found to have partially melted and run away, thus indicating
the exceedingly low freezing temperature of some of the cryohydrate contained in it.
It is quite probable that, had the earlier shafts not been sunk, there would still
have been some liquid brine below the ice in July. As soon as the earlier shafts broke
through to the liquid the latter rushed up and rapidly froze as a uniform, somewhat
yellowish, enamel-like saline ice.
Crystalline structures. The dominant structure was that of a vertical prismatic
arrangement ; such as is typical of liquids freezing from above. Hach prism was seen
to extend in a vertical direction for several inches, some for quite a foot. Near the
surface, where the ice was freshest, cross-sections perpendicular to the long prism axis
showed the average diameter of the individuals to be about a quarter of an inch, whilst
the maximum diameter attained was found to be three-quarters of an inch. At a
depth, where the ice was more saline, the structure gradually changed. Upona glance
8 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
merely, it appeared as if the individuals in the bottom six inches had been reduced in
dimensions, with the production of an aggregate of very even-sized factors averaging
one-eighth of an inch across. Closer inspection revealed a more complicated fabric.
Instead of the prisms with polygonal cross-sections, which prevailed in the ice near
the surface, they were seen to be flattened into the form of plates set vertically, often
interpenetrating or twinned. The optical orientation of adjacent plates was often
identical. Inthis way composite flash-faces were met with as much as two inches square.
Saline matter and gas-bubbles, mechanically held within the ice, had taken up
positions in vertical tracts between the ice-prisms. Such inclusions were quite obviously
elongated in a vertical direction. The saline tracts were more or less opaque and white
in colour. Near the bottom of the lake, where, at the time of freezing, the mother-liquor had
been very saline, the salt content had materially affected the crystallisation and bulked
large in the solidified product. The bottom three inches, which had resulted from the
freezing of a liquid containing about fifteen per cent. of solid matter in solution, afforded
an excellent illustration. On standing at a temperature still well below 32° F. a specimen
of this ice slowly became freed from brine by its draining away. The interspaces once
occupied by brine were soon, for the most part, occupied by air, thus affording oppor-
tunity of examining the crystalline arrangement of the ice-plates. Upon draining for
a while, the specimen showed, in relief, bundles of similarly oriented thin leaves of
ice growing vertically downwards. In the crystallisation, as growth continued by lateral
expansion of the plates, much brine had become imprisoned, so producing the yellowish
enamel-like ice of the deeper zone.
Coming back to the ice forming the first twelve inches below the surface; this appeared
on a casual glance to be quite different to that below, for a strongly marked horizontal
structure, outlined by layers of somewhat flattened spherical gas-bubbles, caught the
eye. The first of the horizontal layers of bubbles was four inches below the surface, the
next three inches farther; then the layers came every half-inch, losing distinctness
altogether at twelve inches. The contents of the bubbles were, no doubt, chiefly air, but
to this it is likely that some sulphuretted hydrogen was added. The prismatic structure
best developed at a depth of fifteen inches persisted more or less definitely to the surface,
though becoming more confused in the upper layers. Stratified layers, each corresponding
to a particular freeze, are a regular feature of lake- and sea-ice. In this case the extreme
freshness of the surface layers suggests crystallisation from fresh water. Perhaps
abundant snow additions fell upon the surface at the time of freezing. If it were not
that the region is disturbed at frequent intervals by violent blizzards, one would be
inclined to suggest that when completely thawed the lake, in the short summer, does
not regain a state of even salinity. The winter freezing results in pushing the salts
downwards, and the extreme density of the lower layers, when thawed the following
summer, also tends to keep the salts to the bottom.
3. ROUND LAKE
For further details see Vol. I, p. 165. A tarn of very small dimensions near the north-
west end of Blue Lake. It averages some thirty yards across, and is only about two
feet deep. When trenched in early April it was found to be frozen to the bottom. The
water contained much chlorides and sulphates, which were so concentrated in the lower
portions as to give it a yellow opaline appearance. The specific gravity of the thaw-
water from this latter was 1:009 at 4° C., and the temperature of commencement of
freezing was 30-95° F. This yellow ice showed strongly the vertical tracts common
to saline ices. These tracts were from one to three inches long in the vertical, and
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 9
terminated at the lower end ina bulb about a quarter of an inch in diameter. The bulbous
extremities were chiefly occupied by gas, but the stems above were almost fully
occupied by saccharoidal crystalline matter. The ice itself was in platy form arranged
in a vertical direction. The plates averaged an eighth of an inch across, but extended
for several inches in the vertical direction. Frequently several adjacent individuals
were in optical continuity, producing flash faces up to three-quarters of an inch across.
4, SHALLOW LAKE
Situated in a slight depression in the lee of the ridge immediately north of the
head of Pony Gully in proximity to Split Rock. On account of the basin being an
of spongy crystalline
fl Ft. 8 Ins. of clear prismatic
Ice becoming less transparent
pif |LOwer down. Stratification losing
H\.<definition below ,outlined by
bubbles up to one sixth inch diam.,
also strings of bubbles arranged
vertically.
6 Ins.
+——_____—__ -2 ff t..
{6 Ins. of transparent platy Ice
with vertical brine tracts.
2 Ins. of white, enamel-like,
Vassilis (granular Cryohydrates.
OURS Ss-Sas2A<— Gravel
Fic. 2. Shallow Lake Section
imperfect contaimer, much of the thaw-water drains away in the summer-time.
The ice-mass is more of the nature of an ice-slab formed by drift accumulations.
During the autumn much of the ice from the fresher portions was quarried for domestic
purposes. Towards one corner, where the basin was well contained, the ice proved to
be very saline. There the ice at the bottom was found to be a completely crystallised
concentrated brine, and so presented specially interesting features (Fig. 2). The
depth of solid ice was not more than two feet six inches, though irregular accumulations
of snow and névé were scattered over the surface. No growth of alga was to be seen there-
abouts. Doubtless the absence of organic growth accounted for the enamel-white colour
of the saline ice from this basin, in distinction to the yellow colour of that from the two
II B
10 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
preceding. The saline constituents were found to be sulphates and chlorides of sodium,
magnesium, calcium, and a small proportion of potassium. The freezing-point of the
water obtained by thawing a sample from the bottom was 27-5° F. The bulk of the ice
showed horizontal stratification strongly outlined by layers of gas-bubbles, each separated
by an average thickness of two inches of clear ice. The bubbles were as much as one-
third of an inch in diameter, and were generally elongated upwards ina short stem. This
clear stratified ice passes upwards through névé into irregular snow-banks. Below it
becomes less transparent and whiter. The last two inches in proximity to the bottom
were highly saline, resembling white enamel at a temperature of —30° F.—evidently
solidified cryohydrates.
The transparent stratified ice of the upper portion of this ice-slab was crystallised in
vertical prisms, continuous from one layer to another. Downwards, the dimensions of
the prisms dwindled pari passu with the increasing salinity ; at the same time they
assumed a leaf-like form, arranged vertically and developed in optically continuous
bundles. Between the “ice-leaves ’’ was frozen brine, easily distinguished by its white,
opaque appearance. This brine was evidently mechanically entrapped during the
development of the leaves. The bundles of “ ice-leaves,” though always in vertical
planes (actually normal to the cooling surface) were set at varying azimuths, and by
intergrowing produced a striking honeycomb structure in which the cells were occupied
by liquid or frozen cryohydric mixtures. This structure was well exemplified in
the bottom two inches, where the brine was highly concentrated. The “ice-leaves ”’
were brought out in relief by slowly warming a specimen until the cryohydric tempera-
ture was reached, when most of the brine drained away. A further critical examina-
tion of a sample from the bottom of the slab showed that in the freezing, as the
mother-liquor becomes more concentrated, the leaves of pure ice forming the cell
walls diminish in thickness with corresponding increase in contained salts. Finally,
where the crystallisation was from a pure cryohydrate, the honeycomb type, exhibit-
ing intersertal structure, sometimes was seen to merge into an even granular texture.
Sections both along the “‘ice-leaves” and across optically continuous bundles show
more or less distinctly the structure known in petrology as poikilitic.
5. BLUE LAKE
For details refer to Vol. I, p. 157. Blue Lake is an extensive fresh-water ice-lake.
Our experience and the evidence adduced show that the ice in this basin never more
than partially melts during a normal summer. A local thaw at the narrows was noted
in midsummer, but the structures exhibited by the ice made it clear that complete
thawing takes place only once in a long period of years. This is particularly interesting
on account of the fact that Murray found microscopic life amongst the remains of alge
frozen at the bottom, and the minute organisms on being thawed at the Hut again
sprang into life.
Qualitative chemical tests showed the ice to be exceptionally pure. Only the faintest
trace of chloride could be detected in that between the surface and four feet. At greater
depths it was even more free from dissolved mineral matter. The specific gravity of a
sample from near the surface gave 1-00005 at 4° C.
Irregular snow-drifts covered the surface of the lake. The particles of such snow
and névé, during the peculiarly warm conditions of summer and early autumn, “sweat”
together, forming a coarser granular mass, very much honeycombed. In the re-
crystallisation of snow standing on prismatic lake-ice, there is a strong tendency for the
prism structure to be continued above in the developing formation ; thus the ice-grains
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES ll
of the new formation are much elongated in the vertical direction. When typically
formed in this way the prisms pass downwards, gradually increasing in size until they
merge with the prisms of the lake ice. In the upper portions a horizontal section
shows clear ice-kernels, the cross-sections of the prisms, separated by much white,
opaque, saccharoidal, and honeycombed interspaces (see Plate II, Fig. 1). The white
interspaces arise from the drawing apart of the grains to fuse with the prism kernels.
Successive horizontal sections below show less and less of the honeycombed interspaces,
eventually passing into clear ice with only occasional bubbles. The modus operand
in the development of this structure is not as clear as it might be, and further information
upon the subject is wanting. Cross-sections of such surfaces often show radial patches
(cf. Plate II, Fig. 2).
Abrasion by wind and snow during the winter produced on portions of the surface
of Blue Lake large horizontal polished areas of this kind of ice. An elegant figured
pattern was thus developed. Where the vertical prismatic arrangement appears, the
term “coralloidal,” as used by David and Priestley, aptly describes it. In summer a
coralloidal surface tends to become exceedingly rough, for ablation proceeds very
rapidly in the spongy mass between the kernels, leaving the latter projecting in relief.
The more rapid ablation of the spongy matrix is owing to the fact that it offers less
bulk for evaporation, more surface relatively, and has a slightly lower melting-point
(for any traces of saline that may have been contained in the snow will be con-
centrated therein) than in the kernels. The individuals of all ice-formations originating
from névé, whether they be prismatic or not, always exhibit tortuous interlocking
boundaries. The normal prismatic ice of lakes is composed of individuals with straight
polygonal boundaries.
The accompanying diagram (Fig. 3) illustrates the section laid bare by Priestley in
a shaft sunk in July near the centre of the southern half of Blue Lake.
In descending order the types met with were as follows :
(1) At the surface there was about one foot of hard snow with specific gravity of
0-46, compacted by the winter blizzards; actually a fine grained névé as the term is
used in Switzerland.
(2) Three inches of a coarse crystalline spongy layer, developed by the recrystal-
sation during the autumn of the bottom portions of the snow under the influence
of warmth below, conducted from the lake-ice, and increasing chill from the autumn
conditions above.
(3) Six inches of coralloidal ice in which there were vertical prisms averaging an
inch in diameter at their base. These prisms frequently coalesced below in intricate
articulating boundaries. This formation doubtless originated from a fall of snow
during the summer, or possibly from a fall of the year before.
(4) Eighteen inches of granular, crystalline ice loaded with bubbles. The individuals
were very regular in size, averaging a third of an inch in diameter. The texture was
hypidiomorphic granular. Occasionally a tendency to short prismatic structure was
revealed. Bubbles were distributed irregularly and abundantly throughout, those near
the top being largest. In the latter position they were noted to frequently attain a
diameter of a quarter of an inch. At a foot below the top of the band eighty-three
were counted in an area of seventy-five cubic centimetres, equal to an average of
1-1 to the cubic centimetre. At that spot the average diameter was a sixteenth of
an inch.
It will be noted that this layer corresponds closely to the ice of old permanent
ice-slabs where there is little movement. It must have originated from the solidifica-
tion of snow-drifts accumulated upon the lake at least two summers before; in all
probability even considerably earlier than that.
12 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
(5) Then came ice with a stratified appearance, arising from the distribution of
bubbles in sheets.
Bands, a couple of inches thick, carrying abundant bubbles alter-
nating with others carrying less bubbles. Here a vertical prismatic structure was
IFt. Hard Snow.
3. Recrystallised Névé.
6. Coralloidal Ice.
18. Granular, crystalline
Ice loaded with bubbles
arranged irregularly.
18. Stratified with
Prism Structure.
|
5 .6.Clear Prismatic Ice
with conchoidal fracture;
Coarser grained above,
finer below
2. Coarse Prismatic Ice
with fragments of alga,etc.
Be Clear, Prismatic Ice
\ with conchoidal fracture
and strong radial flutings.
I. Glear Prismatic Ice
evidencing strain.
ock Bottom with
fragments of alga,etc.
Fic. 3. Blue Lake Section
moderately well defined and, taken in conjunction with the arrangement of bubbles,
is evidence that that ice originated by the freezing of ponded waters.
(6) At about eighteen inches from the top of the stratified bubble-ice the layers
became indistinct and the structure was gradually lost, at the same time the ice became
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 13
strongly prismatic. In that position patches of tube-like bubbles appeared, usually
straight but often winding, averaging a thirty-second of an inch in diameter. At thirty
inches below the surface of the stratified lake-ice prisms were met with as much as
three inches in cross-section and nine inches long. At that horizon the average cross-
diameter was one inch. Occasional bubbles in this part were pear-shaped with the larger
end uppermost.
At, and below this level, the ice was very clear and exhibited a well-developed con-
choidal fracture with distinct flutings across the sweeping curves. These latter radial
flutings became increasingly more strongly marked in the deeper levels. Descending
still further, the prisms began to contract in size so that at a depth of eight feet below
the surface of the coralloidal ice the grain size was found to average a third of an inch.
At that place scattered irregular bubbles were met with, all exhibiting a tendency to
elongation in the vertical direction. A block measuring 450 cubic centimetres was
found to contain twenty-three bubbles, or one per twenty cubic centimetres.
(7) Between the depths of nine feet and eleven feet below the surface of the coralloidal
layer was a band of coarse vertical prismatic ice containing fragments of the red-brown
alga on which Murray found living microscopic life. The fragments of alga were each
enclosed within disc-like gaseous envelopes, the gas apparently breathed out by the
plant and microscopic animals at the time of freezing. Asan instance may be mentioned
a fragment of alga, half an inch in diameter, surrounded by a gaseous disc five inches in
diameter and one-eighth of an inch thick. Adjacent to one of the alga fragments was
a bunch of vertical gas-tubes (see Plate II, Fig. 3). At the ten-foot level a zone of
beautiful tubes was cut through; these had a bulbous extremity below and extended
upwards in a regular stem as much as six inches ; their diameters ranged from a sixteenth
to a twelfth of an inch. A slab of ice from about this level showed tubes from two
inches to three inches long and one-eighth of an inch in diameter. On close inspection
these were found to be beautiful negative hexagonal crystals. As many as 150 were
counted in the slab which, in cross-section, measured 525 square centimetres. Where
more sparse they were larger. Examined with a pocket lens they were found to be drusy
in the interior.
(8) Below eleven feet there was a change in the ice, so concluding the evidence which
indicated that at one time that was the downward limit of thaw for one or more seasons.
From eleven feet onwards bubbles were but occasional. Here and there large
irregular ones showed along old fracture planes which had become recemented. The
ice was still prism-ice, but no individual longer than three inches was noted. The radial
flutings crossing the conchoidal fracture curves were strongly marked.
At fourteen feet to fifteen feet the jarring of the pick developed sets of wavy horizontal
cracks, the planes of which crossed each other and resulted in an appearance reminding one
of augenstructure. Evidently the effect of strain induced by the superincumbent weight.
At fifteen feet the rock bottom was reached. There remains of the alga were
found. In association with it abundant unicellular chlorophyll-bearing organisms,
rotifers, etc., were found still living. The evidence already mentioned goes to show
that these organisms must have been imprisoned there in the frozen state for at least
three years and probably a great deal longer.
In explanation of the persistence of live organisms in the depths of some of the lakes
at Cape Royds, which have remained frozen over in all probability for years, it is
suggested that, as sunlight can penetrate through the ice, so long as there is a balance
between the plant and animal life all will thrive just as well under a roof of ice as
free from it. On account of the lower freezing temperature of saline water, the briny
portions of the lakes are the last to solidify and, except in the deepest lakes, are doubtless
also the first to thaw. As this is so, the organisms should be able to live on for the
14 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
greater part of the year in the still liquid deeper zones. At the same time the evidence
was clear that in some cases the organisms which came to life on being thawed out had
been frozen in such positions for a long time.
6. COAST LAKE
Refer to Vol. I, p. 162. A nearly circular lake averaging about a hundred yards
across. Greatest depth met with, four feet one inch. The distribution of algal peat
Sp. Gr.
Fi, ans. (water)
1.0000 Clears bubbly, prismatic Ice
n horizontal layers.
1.0012 Saline ice.
Nave
Granular ice containing 75%
z-G0Ra by bulk of algal Peat.
N03
as
ASCs
faa
— bes: es
PATNI)
Layers with and without
1.0004 Peat in alternation.
Pie
Rock-rubble on Rock.
Fic. 4. Coast Lake Section
in some of the ice-layers, the character of the crystallisation, and the degree of
salinity at various depths, all indicated that a long period had elapsed since the lake
had been completely thawed. The usual summer condition does not exceed a partial
thaw downwards from the surface.
Specific gravity determinations on the waters obtained by melting samples of the
ice gave as follows :
Sp. gr.
Average bubbly ice between four inches and ten inches. . 1-0000
Prismatic ice between one foot six inches and one foot eleven
inches ; . 1:0012
From peaty layer between two feet and two feet nine inches . 1-0022
Between two feet eight inches and three feet eight inches . . 10004
From the four-inch peaty Pe between three feet PE inches
and four feet : ; : 1-0007
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 15
(1) To a depth of eighteen inches the ice had a strongly marked stratified appear-
ance, owing to the presence of horizontal sheets of gas-bubbles at intervals of half an
inch to one inch (see Plate III). In the lower portions the layers were closer
together and less well defined. The individual crystals were prismatic and of larger
dimensions in the deeper layers. They measured half an inch to one inch across
and from one inch to two inches, occasionally reaching six inches in length. They were
bounded by straight-line faces but showed frequently interlocking junctions. In the
deeper layers the bubbles tended to become elongated in the vertical, usually resulting
in a tube with a bulbous extremity. The needle-like tubes had a diameter not exceed-
ing one thirty-second of an inch.
(2) Next came a six-inch layer of slightly odoriferous saline ice, with salt tracts
between the prisms.
(3) Then there was a nine-inch layer which, in the hand-specimen, had the ap-
pearance of jet, and was found to be composed of the peat-like remains of the alga
already referred to, with a small admixture of grit, all cemented by twenty-five per cent.
in bulk of frozen, somewhat briny water. For many years previously this level must
have represented the downward limit of thaw.
(4) Below the main band of algal peat was a belt one foot four inches thick, consti-
tuted of layers usually from half an inch to two inches thick, charged with more algal
remains alternating with other clear ice-bands. The last four inches of this section were
composed of an extra thick band of algal peat and rested on the bottom of the lake.
In the layers where organic remains were abundant the ice tended towards an even-
sized, granular texture, in which the grains were polygonal, averaging a quarter toa
third of an inch in diameter. Where there was little peaty matter the prism structure
was preserved and extended from one layer to the other.
7. CLEAR LAKE
Refer to Vol. I, p. 154. An elongated lake about one hundred yards in length and
thirteen feet deep where trenched. It was particularly noted for the large area of its
surface, formed of handsomely marked coralloidal ice. In other places snow-drifts lay
on the surface, and beneath them could be traced stages in the formation of the coral-
loidal ice. Where the second shaft was sunk, in April, four inches of the figured ice
at the surface passed down into prismatic ice in which were vertical columns of
bubbles, then bubbles strung like beads, and finally isolated bubbles in vertical
lines. Prismatic structure was marked from the coralloidal surface down, but beyond
the two-feet level became more prominent, and vertical gas-tubes, some of them
negative crystals, appeared. This latter was no doubt ordinary lake ice, but that
above was formed in some other way, partially or wholly, from snow-drift accumulations,
At five feet four inches there appeared to be another line of demarcation, for the ice below
showed only occasional bubbles, was very transparent, and exhibited a conchoidal
fracture. At six feet the crystals were still prismatic, bounded by polygonal faces,
averaging a quarter of an inch in diameter, but from five inches to six inches long.
Often several adjacent crystals were optically continuous, producing faces half an inch
or more across.
The total thickness of the ice was nine feet one inch, and there were some four feet
of water below it. The specific gravity of that water at 4° C. was 1:0014.
16 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
8. GLACIER-ICE (for comparison)
For comparison with the textures of the lake-ices a reference to that of glacier-ice
from the vicinity is interesting.
Asample of the ice at sea-level, about one hundred feet below the surface of the glacier,
one mile south of Cape Barne, was found to be composed of equidimensional grains with
interlocking and re-entrant straight-line boundaries. Some of the grains were an inch
in diameter. It was loaded with bubbles well shown in the photograph (see Plate I,
Fig. 4). The bubbles were very irregular in shape, often spherical or dumb-bell-shaped,
and sometimes tube-shaped. The spherical bubbles were commonly a sixteenth of an
inch in diameter. Where elongated they were found to be leaning at an angle of 45° with
the upper end forward in the direction of motion of the glacier.
Nearer the surface the ice of the glacier passed into a finer grained state.
9. CLASSIFICATION OF THE CRYSTALLINE TEXTURES OF
THE LAKE-ICES
The crystalline texture of the lake-ices has been shown by the foregoing investiga-
tions to depend in the following manner upon the proportion of dissolved salts in the
water :
(a2) Fresh water allows of the formation of coarse prisms.
(b) Somewhat saline water yields medium-sized prisms.
(c) Highly saline water produces plate structure.
(d) Cryohydrates solidify as a fine-grained mass, in which intersertal
structure is often prominent.
IH. SEA-ICE
Refer to The Heart of the Antarctic, Vol. II, p. 337, and Vol. I, p. 180, of this series.
The ice of the first few inches from the surface usually originates as a_ felting
together of small floating crystals. As the freezing in that layer proceeds more
rapidly than in the deeper zone, a larger proportion of brine is trapped in the inter-
stices of the feltwork. Below, the ice is prismatic with saline tracts between the prisms.
As in the case of lake ices, a horizontal stratification is noticeable throughout the first
foot or two below the surface.
Snow piled upon the surface becomes consolidated, and draws up a small quantity
of brine from the salt ice below. The following specific gravity determinations were
made from samples got in a shaft sunk by Priestley in the frozen surface of Back Door
Bay in the winter:
Specific gravity of thaw-
water at 4° C.
First foot : A : : ‘ : . 1:0084
Second foot 3 : : 4 : é . 1:0046
Third foot : : : ; : ; . 1:0043
Fourth foot : ; A : ‘ , . 1:0026
Fifth foot , : ‘ ; > , . 1:0061
A sample of the surface sea-water of McMurdo Sound, taken about the same time, on
an occasion after a blizzard had cleared the floe out, had a specific gravity at 4° C. of
1-:0275.
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES lke
The reason for the high specific gravity of the first foot of the sea-ice has been men-
tioned. Below, as the crystallisation becomes slower, expulsion of the salt is increasingly
more effective. The fifth foot, which was in contact with the sea-water below, was
somewhat cellular and saturated with sea-water, which did not all drain out before
part became frozen in the specimen, hence the greater salinity.
IV. ICE-STALACTITES
Besides fresh-water icicles there were to be found along the ice-foot which formed
at Cape Royds grottos draped with stalactites of less simple structure. The ice of
the ice-foot is in all cases very briny, consisting largely of frozen sea-spray. On account
of the fact that the melting-point of brine is very much below that of pure ice, there is
Hollow Core Cellular Layers
Fic. 5. Cross-Section of Stalactite
a tendency for the former to ooze out of the ice-foot and drip back into the sea. As
the freezing of brine solution depends upon its concentration, the brine which drips
from the ice-foot at low temperatures is more concentrated than that at high tempera-
tures. In the autumn, with falling temperatures, the brine which oozes from the ice-
face becomes somewhat more chilled before it has time to drop, and so leaves behind at
that point a little pure ice. In time the dripping-point becomes more pronounced and
stalactites, sometimes several feet in length, are built up gradually. A stalactite from
the ice-foot at the Penguin Rookery was examined and found to be constructed of
alternating concentric rings of compact ice and of cellularice. The centre was in the form
of a somewhat cellular hollow tube. The section figured here is a reproduction of the
cross-section traced from the stalactite itself (Fig. 5).
On thawing a stalactite the commencement of freezing of the thaw-water was found
to be 29-5° F.
A quantity of the drip from stalactites at the ice-foot was collected in the early
autumn and found to commence freezing at 8° F. At —5° F. it had assumed the form
of a paste—a mixture of unfrozen cryohydrate and fine ice-leaves.
After the sea in the vicinity had become finally frozen over, snow drifting over
the floe banked up along the shores, obliterating much of the original ice-foot. Where
stalactite-draped caverns remained, the stalactites themselves were found to have
It Cc
18 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
developed into grotesque forms by additions of firmly adhering snow (see Plate IV,
Fig. 2).
A further case worthy of note was that which was presented in a cavern of a large
‘ snow-berg ” held in the floe near Cape Barne. The berg, though rather a small one,
was originally of the table-topped class. All that was exposed above the sea was
fine granular névé, firmly consolidated in the lower portions. Owing chiefly to
weathering of the summit, it rose somewhat out of the water during the winter, and
exposed a large cavern that had formerly been eaten out below sea-level by the wash of
the water. Near the water-level, sixty feet below the summit, the berg was composed of
fine granular particles averaging one-thirtieth of an inch in diameter, whilst many
of the grains reached a twentieth of an inch in diameter. Though well compacted,
the névé in that part of the berg was sufficiently porous to have been saturated with
sea-water. So it happened that, as the berg rose, the brine kept oozing from the roof of the
cave, developing well-formed stalactites (see Plate IV, Fig. 1).
When the photograph was taken the temperature was -30° F., and there was but a
slight drip, which completely froze on the floor as mamillary stalagmites having the
appearance of white enamel—evidently frozen cryohydrate. The stalactites showed the
usual rings in cross-section, were resinous in appearance, and exhibited a conchoidal
fracture. Towards their downward extremities the internal appearance changed to
that of a fine granular texture. To what extent this was due to adhering drift-
snow or to the freezing of certain cryohydrates with higher freezing-point was not
ascertained.
V. A COMPARATIVE STUDY OF ICE-CRYSTALLISATIONS
FROM VAPOUR
The amount of water vapour necessary to produce saturation in the atmosphere
varies with the temperature. Approaching the freezing-point, 32° F., it sinks to a small
fraction of what it is at higher temperatures. Below freezing-point, saturation is
attained when there is little more than vestiges of water vapour in the air. In a land
where almost all is ice, notwithstanding the fact that at such low temperatures the
capacity of the atmosphere for moisture is trivial, great results follow from the offices
of the atmosphere in taking up, transporting, and depositing H,O. For the most part
it is evaporation of a solid and deposition as a solid, and is thus a case of sublimation.
An experiment was entered upon with the object of ascertaining whether vapourisa-
tion is accelerated in the case of saline ices. A metal mould for casting cylindrical blocks
of regular dimensions was made. In it a series of blocks was cast, each about two
pounds twelve ounces in weight. There was a block of fresh-water ice, and others with
certain ingredients added in molecular proportions : e.g. NaCl, Na,SO,, KCl, MgSO,,
and MgCl,. The blocks were suspended on gibbets on the south side of the Hut, as
shown in Plate XCI, Vol. I. What with the interference of an occasional blizzard and
certain inherent difficulties the experiment was not altogether a success. However,
sorting over the results of a large number of weighings, one is struck by a general
accordance indicating more rapid ablation in the saline ices.
A theoretical consideration of the case suggests that the presence of salt might
accelerate evaporation in the region of the temperature scale not far below the
freezing-point of fresh water, but that its effect in this respect would be lost at
lower temperatures.
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 19
Interesting observations on ice forms developed under varying conditions were
made within the precincts of the Hut itself. In explanation of subsequent statements,
brief mention of the plan of the Hut is necessary. The Hut was entered by an outer
door, then along a short vestibule and through an inner door. The Low-temperature
Laboratory was a small, tightly enclosed room outside the main room of the Hut, and was
entered by a door in one of the walls of the vestibule. From the Low-temperature
Laboratory a scramble on hands and knees under the floor of the vestibule brought
one to Wild’s Store, another well-enclosed adjunct to the Hut. The cooking-range, the
only source of heat, was at the end of the Hut remote from the entrance door. Near
the stove the temperature would be well above 32° F. and it fell off regularly en route
to Wild’s Store. The journey to the latter was quite a long and devious one, and along
the path there was usually a slight current of air, particularly when the inside door of
the Hut was opened. The average winter temperature in Wild’s Store ranged from
-20° F. to -30° F. As giving some idea of the conditions in the Low-temperature
Laboratory, it may be mentioned that on one occasion when the outside temperature
was —20° F. that in the Low-temperature Laboratory was —6° F.
Moisture rising from the cooking and from our breath kept the air in the Hut fairly
well saturated. Much of this was continually depositing as a fuzzy coating in odd
corners where low temperatures prevailed, particularly on the inside of the inside door.
All such deposits were, however, of little interest, because they never remained long
enough to develop pronounced structure before being destroyed by partial thaw as a
result of the wide range of temperature experienced within the Hut.
(a) Crystallisations from Concentrated Vapour.
In the vestibule snowy growths, usually of a fluffy character, formed on the walls
and ceiling so rapidly that it required to be scraped out at very frequent intervals. Thus
was exemplified crystallisation from a copious supply of over-saturated atmosphere, at
temperatures not greatly below freezing-point. ‘The draught causing rapid carriage
of the vapour was certainly a factor in determining its fluffy character.
Similar conditions pertained in the stable, where the breath from the ponies poured
forth a copious vapour which froze in beautiful fern-like forms attached to the ceiling and
on hanging objects (see Plate V, Fig. 1).
The flocculent snow, in delicate flakes, which falls durmg the Antarctic summer,
and more rarely at other times during the year near the sea-board, is of this class.
(b) Crystallisations from an Attenuated Vapour.
At lower temperatures, even at 100 per cent. humidity, the vapour is attenuated
and the precipitation is modified, as exemplified by the formation which appeared in
the Low-temperature Laboratory (see Plate VI, Fig. 2). Deposition
was much slower there than in the vestibule. However, a coating
of blade-like forms, standing perpendicular to the walls and ceiling,
gradually developed (see Plate VI, Fig. 1). In this formation each
blade is a composite basal plate built up of innumerable, almost
microscopic scales, each with trigonal symmetry as shown in the
sketch (Fig. 6).
These small units remind one of forms which compose the py, 6 Iee-Scale with
precipitation during certain Antarctic winter snowfalls. Trigonal Symmetry
Reference to a form of platy crystallisation has been made by
David and Priestley (Vol. I, p. 19). The details there mentioned are not quite clear,
however, and something more may be added. On that occasion, as we sledged along
over the hard névé surface of the plateau on a bright sunny day, a carpet of ice-blades
20 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
began to grow up from the surface névé. In a few hours it was just as if we were
walking on a velvet-pile carpet. The wind sprang up later on and mowed down the
crystal plates. They reminded me at the time of the flakes of flake anthracene. These
delicate plates were formed from vapour rising out of the comparatively warm porous
névé below, and becoming chilled by the air temperature.
The ‘“‘ice-flowers ” of the newly frozen sea are composed of plates similar to
those of the Low-temperature Laboratory. Each “flower” is composed of an inter-
penetrating bunch of these composite plates, and may be so well developed as to reach
a diameter of two inches (see Plate V, Fig. 2). In the case of a typical crop which
formed over Back-Door Bay in the autumn, the thickness of the plates was found to
be a two-hundred-and-fiftieth of an inch. Favourable conditions for the growth of ice-
flowers are a dead calm and a sudden fall of the temperature to zero or lower.
Growth takes place by additions to the plates from atmospheric moisture replenished
from the comparatively warm thin ice layer over the sea-water. It was found that,
normally, the nuclei for the building up of these rosettes is brine—drops of brine
exuded by the hardening sea-ice below. If, therefore, a sample of ice-flowers be
collected and thawed, brine and not fresh water is the result. As indicating the
degree of salinity may be mentioned determinations of the beginning of freezing
of the brine obtained by thawing two samples. One, marked “ large old ice-flowers,”
commenced to freeze at 27-77 F.; the other, distinguished as “small young ice-
flowers,” gave 20° F. Obviously, as they grow in size, the original brine is continually
diluted. A more irregular growth of the kind is that which throughout the winter
is seen to form around the margins of cracks in the sea-ice and over newly frozen
leads. In such situations the “ flowers ” are more fluffy and fern-like, and the brine
nuclei may be dispensed with altogether, the deposition taking place more or less at
random on any exposed objects. Like growths are seen on the surface of sheets of
fresh water—in all cases freezing takes place at low temperatures. For instance, on the
freezing surface of water exposed by trenching operations in the winter on the lakelets
around Cape Royds.
Akin to these plates formed from depositions from rarefied vapour are the leaf-like
plates which are typical of ice forming as separations from concentrated brines. Crystal-
lisations of the kind have been mentioned as forming the lowest and most briny zones of
Green Lake and of Shallow Lake. Separations of the kind were also well illustrated
as developing from sea-water under certain conditions ; for example, adhering to ropes
left freely suspended in sea-water. An instance of the kind is figured on Plate XXVI
of Vol. I. Asample of such plates was allowed to drain at a temperature of about zero F.,
then thawed, and the freezing-point of the liquid determined. Freezing was found to
commence at 31-7° F., illustrating the freshness of the crystals.
(c) Crystallisations from Rarefied Vapour.
A glance into Wild’s Store supplied valuable information in this connection.
Adhering to cans of preserved food and on the ceiling were beautiful crystals of clear
ice with more or less perfect shape. The ideal form was that of a short hexagonal prism
limited by basal planes. In situations where the air current was greater, skeleton forms
were the result, and some of these were found so large as to represent portions of hexagons
three-quarters of an inch across.
A good example of the same type of formation was met with in the spring on digging
up a seal liver which had been buried in the snow during the winter. The lower side
of the liver was covered with perfectly formed short prisms of clear ice (see Plate VII,
Fig. 2).
This form of crystallisation is universal on the walls of crevasses, and in such situations
A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES 21
the size of the individuals is often very large. During the winter the moister air from
below rises in the crevasse, and as it is chilled nearing the surface, crystals are deposited
on the walls. In summer-time, no doubt, additions are made from moist air entering
from above. Soa spongy mass of crystals is developed which, in time, chokes the mouth
of the crevasse.
Frost-ice, which forms at low temperatures, is of this class. The duration of any
particular frost-period is usually so short that in cases where the temperature is below
zero F’. the deposition is scarcely perceptible to the eye, but is readily felt as a sort of
sand-paper coating on all exposed objects. Attention was particularly drawn to this
frost-ice on account of its interference with the lenses of the spectroscopic camera when
exposed for long intervals during the winter night. Plate VII, Fig. 1, is a photograph
of the front of the spectroscopic camera on an occasion when it showed an abundance of
frost-spicules. Frosts of the kind of which I am speaking took place at temperatures
below zero F., that illustrated having formed at —30° F.
Analogous with this class is the precipitation from a cloudless sky occasionally
experienced at sea-level during the winter, and even in the height of summer on the
plateau. Such falls are composed of minute, well-formed, clear crystals. The mean
dimensions of the particles of a fall during the winter at Cape Royds was found to be
one-hundredth of aninch. Many of the wonderful optical effects witnessed on occasions
in the Polar regions is due to the presence of these particles floating in the atmosphere.
In conclusion it is to be remarked that the subject of vaporisation and redeposition
of ice is a most important one, for it is by such processes that snow becomes converted
into névé and is also largely accountable for the convertion of névé into ice. Loosely
packed snow holds a large volume of air which is ever taking up and redepositing ice
part passu with fluctuations of the temperature and barometric pressure. Thus the
individual grains become increased in size and the pore space reduced in accordance with
the well-known laws governing recrystallisation under such conditions.
VI. EXPLANATION OF THE PLATES
(All Photographs and Diagrams by the Author)
PLATE I
FrGurE 1.—A winter moonlight view of Green Lake from near High Peak, looking West ;
the Lake nestling below the figures; the frozen sea in the distance extending to the
horizon.
FIGURE 2.—Showing a pebbly slope near Green Lake. In the lee of the pebbles white
accumulations of saline matter resembling snow are visible.
PLATE II
Figure 1.—Coralloidal ice, Clear Lake. A photograph looking down upon it from
three feet above.
Figure 2.—The same showing a centric development.
Figure 3.—Vertical bubbles in the ice of Blue Lake; ten feet below the surface.
(Enlarged. )
FicuRE 4.—Photograph of ice from 100 feet below the surface of a glacier near Cape
Barne illustrating the bubbles. (About natural size.)
PLATE III
Stratified bubbly ice from the surface zone of Coast Lake. The top of the block was
the actual surface. The white triangular patch on one side is “scar tissue,”
which formed in a crack from vapour from below. In this way the crack was
eventually closed up. (Reduced in size.)
PLATE IV
FicurE 1.—Stalactites draping a cave in a tilted “‘ snow-berg ”’ near Cape Barne.
FIGURE 2.—Stalactites which have assumed grotesque forms owing to snow additions,
in a cavern under the ice-foot at Cape Royds.
PLATE V
Figure 1.—Fern-like skeleton crystals adhering to a piece of string in the pony stables.
The “ fronds ”’ were up to two inches in length.
Figure 2.—Ice-flowers on the newly frozen sea, Back-Door Bay. The bunches were
about two inches in diameter.
23
24 A CONTRIBUTION TO THE STUDY OF ICE-STRUCTURES
PLATE VI
FicurE 1.—Looking from a distance of twelve inches into a growth of composite blade-
like ice-crystals formed on the wall of the Low-temperature Laboratory.
Figure 2.—A distant view of the same.
PLATE VII
Ficure 1.—Frost-ice formed at —30° F. on the face of the spectroscopic camera.
Figure 2.—Hexagonal crystals of clear ice formed by sublimation on a seal liver which
had been buried during the winter.
FIGURES IN THE TEXT
1. Diagrammatic representation of the section at Priestley’s July shaft in vo
Green Lake
2. Section of Shallow Lake
3. Priestley’s July shaft in Blue Lake 12
4. Section exposed in Priestley’s shaft, Coast Lake 14
5. Cross-section of stalactite developed from a brine solution. (Actual
size) 7
6. Ice-scale with trigonal symmetry ; a unit in plate formation. (Greatly
enlarged) 19
PLATE
Vic. 1. GREEN LAKE VIEWED FROM NEAR HIGH PEAK
Iic. 2. SALINE ACCUMULATIONS (NOT SNOW) IN LEE OF PEBBLES,
CAPE ROYDS
[To face p. 2
PLATE II
Ie. 3
FE.
ic. 1
4
HIG. 4
2
=
Fic.
PLATE III
STRATIFIED BUBBLY ICE FROM THE SURFACE ZONE OF
COAST LAKE
PLATE IV
Fic. 1. STALACTITES OF A CAVE IN A “SNOW-BERG ”
Fic. 2. STALACTITES OF GROTESQUE FORM UNDER THE ICE-FOOT
PLATE V
Fic. 1. FERN-LIKE SKELETON CRYSTALS ADHERING TO A CORD
Fic. 2. ICK-FLOWERS ON THE NEWLY FROZEN SEA-ICE
PLATE VI
Fic. 1. A CRYSTALLISATION OF PLATY ICE ON THE LABORATORY
WALL VIEWED AT A DISTANCE OF TWELVE INCHES
Fic. 2, A DISTANT VIEW OF THE CRUST OF PLATY ICE FORMED
ON THE LABORATORY WALL
PLATE VII
Fic. 1. FROST-SPICULES FORMED AT —30° F. ON
THE FACE OF THE SPECTROSCOPIC CAMERA
Fic. 2. HEXAGONAL CRYSTALS OF ICE SUBLIMED ON
A FROZEN SEAL LIVER
PART II
REPORT ON THE FORAMINIFERA
AND OSTRACODA
FROM ELEVATED DEPOSITS ON THE SHORES OF
THE ROSS SEA
(With Six Plates)
BY
FREDERICK CHAPMAN, A.L.S., F.R.M.S.
Palzontologist to the National Museum, Melbourne
CONTENTS
SECTION
I. FORAMINIFERA FROM UPTHRUST MUDS ABOVE THE DRYGALSKI
GLACIER, SOUTH-EAST OF MOUNT LARSEN : :
GENERAL REMARKS ON THE COLLECTION
DESCRIPTION OF THE FORAMINIFERA
EXPLANATION oF PuateEs I-III
Il. OSTRACODA FROM UPTHRUST MUDS ABOVE THE DRYGALSKI GLACIER,
SOUTH-EAST OF MOUNT LARSEN
GENERAL REMARKS ON THE COLLECTION
DESCRIPTION OF THE OSTRACODA.
EXPLANATION OF PLATE IV
Ill. FORAMINIFERA FROM ELEVATED DEPOSITS ON THE SLOPES OF
MOUNT EREBUS, NEAR CAPE ROYDS
GENERAL REMARKS ON THE COLLECTION
DESCRIPTION OF THE FORAMINIFERA
EXPLANATION OF PLATE V .
IV. OSTRACODA FROM ELEVATED DEPOSITS ON THE SLOPES OF MOUNT
EREBUS, NEAR CAPE ROYDS :
GENERAL REMARKS ON THE COLLECTION
DeEscRIPTION OF THE OSTRACODA.
EXPLANATION OF PLATE VI
PAGE
wnmn WwW
aks N
SECTION I
FORAMINIFERA
FROM UPTHRUST MUDS ABOVE THE DRYGALSKI GLACIER, SOUTH-
EAST OF MOUNT LARSEN
GENERAL REMARKS ON THE COLLECTION
Tuts deposit is a bluish-grey calcareous clay or ooze, in which the larger foraminifera
and echinoid spines are conspicuous. It was collected by Prof. T. W. Edgeworth
David from a marine deposit about twenty feet above sea-level, just north of the
Drygalski Glacier, December 22 and 23, 1908.
The collection of Foraminifera obtained by washing the material, although not
very rich in species, nevertheless presents several points of much interest. The
majority of the larger tests belong to Biloculina, Nodosaria (Glandulina), Cassidulina,
and T'runcatulina. The two former genera are almost equally abundant. By the
occurrence of Biloculina sarsi we have additional and weighty evidence in support
of the bipolar theory of the distribution of marine life, for that particular species forms
a large proportion of the “‘ Biloculina Clay” of the North Sea. Further evidence in
this direction is afforded by the glanduline form of Nodosaria occurring here, as well
as Truncatulina refulgens, another of the abundant forms in this deposit, and
Nonionina stelligera.
Notwithstanding the presence of many unrestricted species, as regards depth of
habitat, there is a considerable proportion of deep-water forms like Cassidulina
subglobosa, Ehrenbergina pupa, E. serrata, and Cristellarva convergens ; and this leads
one to conclude that the deposit may have been formed at a depth certainly of about
100 fathoms, if not greater.
Twenty-four species are here recorded, twelve of which have already been noted
from the sub-Antarctic islands of New Zealand. The species apparently new to this
area are Biloculina levis, Bulimina seminuda, Virgulina schrerbersiana, V. subsquamosa,
Cassidulina parkeriana, Ehrenbergina pupa, Nodosaria (Glandulina) levigata, N. (GI.)
rotundata, Cristellaria convergens, Discorbina vesicularis, D. vilardeboana, and Nonionina
stelligera.
DESCRIPTION OF THE FORAMINIFERA
Family—MILIOLID
Sub-Family—MIioLinin&
Genus—Biloculina, d’Orbigny, 1826
Biloculina depressa, d’Orbigny (Plate I, Figs. la, 1b, 2, and 8)
Biloculina depressa, VOrbigny, 1826, Ann. Sci. Nat., vol. ‘vil. p» 2985; No. 7:
H. B. Brady, 1884, Rep. Chall., vol. ix, p. 145, Pl. U, Ries 12165) 174 els ay
27
28 REPORT ON FORAMINIFERA AND OSTRACODA
Figs. 1, 2. Schlumberger, 1891, Mém. Soc. Géol. France, vol. iv, p. 547, I, IS,
Figs. 48, 49; woodcuts, Figs. 1-5. Chapman, 1907, Jowrn. Linn. Soc. Lond., Zool.,
vol. xxx, p. 14, Pl. I, Fig. 16. Idem, 1909, Sub-Antarctic Islands of New Zealand,
vol. i, art. xv, p. 313.
This species is the most abundant of the Biloculine in the present material.
A feature of some of the tests is the notching of the carina, but they are not regularly
serrated as in B. serrata. Others show a transition into B. levis by the salient
character of the carina of the penultimate chamber.
B. depressa is a widely distributed form, and is apparently unrestricted as to
depth. Sir John Murray gives the bathymetrical range as shore to 3000 fathoms.
Fossil examples, of smaller size than usual, are found in the Tertiary (Baleombian
and Kalimnan) beds of Victoria.
Biloculina levis, Deirance, sp. (Plate I, Fig. 4)
Pyrgo levis, Defrance, 1824, Dict. Scr. Nat., vol. xxxii, p. 273; Atlas,
Pl. LXXXVIII, Fig. 2. Biloculina levis, Defr., sp. H. B. Brady, 1884, Rep.
Chall., vol. ix, p. 146, Pl. Il, Figs. 13, 14. Goés, 1894, Kongl. Svenska Vetenskaps
Akad. Handl., vol. xxv, p. 119, Pl. XXIV, Figs. 914-918. Chapman, 1907, Journ.
Linn. Soc. Lond., Zool., vol. xxx, p. 14, Pl. I, Fig. 15.
Typical specimens are rare in the present series. B. levis has been recorded by
the Challenger from two stations in the N. Atlantic at 390 and 1215 fathoms, and in
shallow water from Papua.
It is well known as a Tertiary fossil, and has been noted from the southern
hemisphere in the Port Phillip Tertiaries (Balcombian series) by the writer.
Biloculina sarsi, Schlumberger (Plate I, Figs. 5a, 5b)
Biloculina sarsi, Schlumberger, 1891, Mém. Soc. Zool. France, vol. iv, p. 553,
Pl. IX, Figs. 55-59; woodcuts, Figs. 10-12. Chapman, 1907, Journ. Linn. Soc.
Lond., Zool., vol. xxx, p. 14, Pl. I, Figs. 1, 2. Idem, 1909, Sub-Antarctic Islands of
New Zealand, vol. i, art. xv, p. 314, Pl. XIII, Fig. 3.
As previously noticed, this species occurs in the “ Biloculina Clay ” of the North
Sea, in material obtained at a depth of 2000 fathoms. M. Schlumberger, in describing
the species, states it to be there very abundant.
So far as we know at present, B. sarsi first appeared in the southern hemisphere ;
for it occurs in the Tertiary beds of Upper Oligocene or Lower Miocene age (Balcombian)
of Port Phillip, Victoria. The fossil shells do not attain such large proportions as the
living or subrecent examples.
Biloculina elongata, d’Orbigny (Plate II, Fig. 6)
Biloculina elongata, VOrbigny, 1826, Ann. Sci. Nat., vol. vii, p. 298, No. 4.
H. B. Brady, 1884, Rep. Chall., vol. ix, p. 144, Pl. Il, Figs. 9a, 9b. Schlumberger,
1891, Mém. Soc. Zool. France, vol. iv, p. 553, Pl. XI, Figs. 87, 88; Pl. XII, Fig. 89;
woodcuts, Figs. 35, 36. Chapman, 1907, Journ. Linn. Soc. Lond., Zool., vol. xxx,
p. 15, Pl. I, Fig. 14. Idem, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv,
oh Oe
The tests of this species are very variable in the present collection, but are distin-
guished from their congeners by the generally elongate form, the comparatively small,
REPORT ON FORAMINIFERA AND OSTRACODA 29
almost circular, aperture with definite T-shaped valve, and the rounded periphery.
The tests are here unusually large, occasionally attaining a length of 2°25 mm.
B. elongata is a well-distributed species, occurring most frequently in moderately
shallow water in temperate seas, and in deeper water in the tropics. In the southern
hemisphere it has been recorded off Heard Island, off Kerguelen Island, and south-
west of Patagonia, from 20-245 fathoms. Sir J. Muwray gives its bathymetrical
range as shore to 2025 fathoms. Small examples in the fossil condition have been
found in the Tertiary (Balcombian and Kalimnan) beds of Victoria.
Genus—Miliolina, Williamson, 1858
Miliolina tricarinata, d’Orbigny, sp. (Plate II, Figs. 7a, 70)
Triloculina tricarinata, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii, p. 299, No. 7.
Miholina tricarinata, d’Orb., sp. H. B. Brady, 1884, Rep. Chall., vol. ix, p-. 165,
Pl. III, Figs. 17a, 176. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. 1,
art. xv, p. 320.
The distribution of this form is very wide. It extends from the Arctic seas to
the Antarctic ice-barrier, and is found at all depths to 2350 fathoms.
The only specimen found here is very small, and suggests a moderately deep water
habitat.
Sub-Family—PENnEROPLIDINE
Genus—Cornuspira, Schultze, 1854
Cornuspira involvens, Reuss, sp. (Plate II, Fig. 8)
Operculina involvens, Reuss, 1849, Denkschr. k. Akad. Wiss. Wien, vol. i, p. 370,
Pl. XLVI, Fig. 20. Cornuspira involvens, Reuss, sp. H. B. Brady, 1884, Rep. Chall.,
vol. ix, p. 200, Pl. XI, Figs. 1-3. Egger, 1893, Abhandl. d. k. bayer. Akad. Wiss.,
cl. 1, vol. xviii, Abth. 11, p. 246, Pl. III, Figs. 18, 19. Chapman, 1909, Sub-Antarctic
Islands of New Zealand, vol. i, art. xv, p. 325.
This is another of the species found in the most northerly sounding made by the
British North Polar Expedition of 1875-76. It occurs, generally speaking, in shallow
to moderately deep water, but has been dredged from one depth as great as 1900
fathoms. Two examples, one fragmentary, occur in the present deposit.
Family—TEXTULARIIDA
Sub-Family—BuLiminin&
Genus—Bulimina, d’Orbigny, 1826
Bulimina seminuda, Terquem (Plate II, Figs. 9a, 9b)
Bulimina seminuda, Terquem, 1882, Mém. Soc. Géol. France, sér. 3, vol. ii,
mém. ui, p. 117, Pl. XII, Fig. 21. B. elegantissima, d’Orbigny, var. seminuda,
Terquem. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 403, Pl. L, Figs. 23, 24. °
The specimen now figured under the above name is a juvenile form of the species.
The general plan of structure is that of B. elegantissima, but the stouter build and
sometimes aborally striate shell, especially the first-named characteristic, gives
sufficient ground to regard this modification as a well-established form. It is, in fact,
a peculiarly southern type of the better-known Arctic, N. Atlantic, and sometimes
S. Pacific species, B. elegantissima.
30 REPORT ON FORAMINIFERA AND OSTRACODA
The example in the present series also reminds one of Bulimina contraria, Reuss,
sp., which differs, however, in showing * no real alternation of segments.” *
Genus—Virgulina, VOrbigny, 1826
Virgulina schreibersiana, Czjzek (Plate I, Fig. 10)
Virquina schreibersiana, Czjzek, 1848, Haidinger’s Naturwiss. Abhandl., vol. ii,
p. 147, Pl. XIII, Figs. 18-20. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 414,
Pl. LIT, Figs. 1-3. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 291, Pl. XX XVIII,
Fig. 6.
Widely distributed both in the northern and southern hemispheres. Its bathy-
metrical range is from 10 to 3000 fathoms. A small example found, having the aboral
end acutely terminated.
Virgulina subsquamosa, Egger (Plate II, Fig. 11)
Virgulina subsquamosa, Egger, 1857, Neues Jahrb. fiir Min., etc., p. 295, Pl. XII,
Figs. 19-21. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 415, Pl. LIT, Figs. 7-11.
This species, like the preceding, has an extensive geographical distribution, and
is found in soundings from shallow to deep water alike.
A minute example occurs in the present collection.
Sub-Family—CassIDULININE
Genus—Cassidulina, d’Orbigny, 1826
Cassidulina oblonga, Reuss (Plate II, Figs. 12a, 126)
Cassidulina oblonga, Reuss, 1849, Denkschr. Akad. Wiss. Wien, vol. i, p. 376,
Pl. XLVIII, Figs. 5, 6. C. crassa, d’Orb. (pars). H. B. Brady, 1884, Rep. Chail.,
vol. ix, Pl. LIV, Fig. 4. C. oblonga, Reuss, Chapman, 1909, Sub-Antarctic Islands
of New Zealand, vol. i, art. xv, p. 332.
This species is moderately abundant in the raised beach material. Its more
elongated test serves to distinguish it from C. crassa, with which it is often confused.
C. oblonga has been dredged off W. Africa, off Cape Town, in the Mauritius, off
the West Australian coast, near Kerguelen Island, and north of Enderby Island in
the subantarctic group. Other localities might be cited but for the difficulty of
discriminating between references to this species and C. crassa.
Cassidulina parkeriana, Brady (Plate II, Fig. 13)
Cassidulina parkeriana, H. B. Brady, 1881, Quart. Journ. Mier. Sci., N.S., vol. xxi,
p- 59. Idem, 1884, Rep. Chall., vol. ix, p. 432, Pl. LIV, Figs. 11-16.
This is by far the commonest species occurring in the deposit. The series of
specimens selected from the washings shows all stages of the test from the sub-ovoid
to the distinctly crosier-shaped shell. The sutures are well impressed, and the aperture
is an elongate pyriform orifice. The majority of the examples, however, present the
appearance of Fig. 14 of the Challenger Report (loc. cit.). Hitherto the species has
occurred at three stations amongst the islands on the west coast of Patagonia at
depths from 45-175 fathoms.
* H. B. Brady, in Rep. Chall., vol. ix, 1884, p. 409.
REPORT ON FORAMINIFERA AND OSTRACODA 31
Cassidulina subglobosa, Brady (Plate Il, Fig. 14)
_ Cassidulina subglobosa, H. B. Brady, 1884, Rep. Chall., vol. ix, p. 430, Pl. LIV,
Figs. 17a-l7c. Egger, 1893, Abhandl. k. bayer. Akad. Wiss., cl. ii, vol. xviii,
Abth. ui, p. 304, Pl. VII, Figs. 41, 42, 52, 53. Chapman, 1909, Sub-Antarctic Islands
of New Zealand, vol. i, art. xv, p. 332.
The Challenger found this to be a deep water species. It has, however, been obtained
in 110 fathoms off Great Barrier Island, New Zealand, and in dredgings at 60 and
85 fathoms round the sub-Antarctic islands of New Zealand.
Two examples only.
Genus—Ehrenbergina, Reuss, 1849
Ehrenbergina pupa, d’Orbigny, sp. (Plate IL, Figs. 15a, 15d)
Cassidulina pupa, V Orbigny, 1839, Foram. Amér. Mérid., p. 57, Pl. VIL, Figs. 21-23.
Ehrenbergina pupa, d’Orb., sp. H. B. Brady, 1884, Rep. Chall., vol. ix., p. 433, Pl. LV.,
Figs. la, 1b, Pl. CXIII., Figs. 10a-10c.
One example of this rare species occurs in the upthrust mud. It has been recorded
from the N. Atlantic, but typically occurs along the coast of South America. It is a
moderately deep water species.
Ehrenbergina serrata, Reuss (Plate II, Figs. 16, 17)
Ehrenbergina serrata, Reuss, 1849, Denkschr. d. k. Akad. Wiss. Wien, vol. 1, p. 377,
Pl. XLVIII, Figs. 7a-7c. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 434, Pl. LV,
Figs. 2-7. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv,
p- 332, Pl. XV, Fig. 2.
This species is not uncommon in the present series, and is represented in every
stage of growth. Like the foregoing, it usually affects fairly deep water. It occurred,
however, in the exceptionally shallow sounding of 50 fathoms off Bounty Island, south
of New Zealand.
Family—LAGENIDA
Sub-Family—LacGEeniInz
Genus—Lagena, Walker and Boys, 1784
Lagena squamosa, Montagu, sp. (Plate III, Fig. 18)
Vermiculum squamosum, Montagu, 1803, Test. Brit., p. 526, Pl. XIV, Fig. 2.
Lagena squamosa, Montagu, sp. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 471,
Pl. LVII, Figs. 28-31. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. 1,
art. xv, p. 335, Pl. XV, Fig. 5.
A solitary specimen occurs in the present collection ; small, but otherwise typical.
The species is unrestricted as to depth, but is found more usually in shallow
water.
Sub-Family—NoposaRtn&
Genus—Nodosaria, Lamarck, 1816
Sub-genus—Glandulina, d’Orbigny, 1826
Nodosaria (Glandulina) levigata, d’Orbigny (Plate III, Fig. 19)
Nodosaria (Glandulina) levigata, d’Orbigny, 1826, Ann. Sei. Nat., vol. vii, p. 252,
Pl. X, Figs. 1-3. Glandulina levigata, d’Orbigny, 1846, Foram. Foss. Vienne, p. 29,
32 REPORT ON FORAMINIFERA AND OSTRACODA
Pl. I, Figs. 4, 5. Nodosaria (Glandulina) levigata, @Orb. H. B. Brady, 1884,
Rep. Chall., vol. ix, p. 490, Pl. LXI, Figs. 17-22, 32. Goés, 1894, Kongl. Svenska
Vetenskaps Akad. Handl., vol. xxv, p. 71, Pl. XIII, Figs. 702, 706. Millett, 1902,
Journ. R. Micr. Soc., p. 509, Pl. XI, Fig. 1.
A few typical examples of this species are found in the present series. An inter-
mediate type also occurs, which, in its asymmetrical, oblique test, approaches Reuss’s
genus Psecadium.* The affinities of the latter type of shell are with the glanduline
forms of Nodosaria, and probably merely represent an abnormal condition amounting
to deformity induced by injury of the usually symmetrical test. Hitherto these
asymmetrical glanduline shells appear to have been confined, with the exception of
Goés’ example, to a few fossil specimens figured by Reuss and Costa. The aperture in
the specimens before us is depressed, and of the stellate type.
This species is yet another of those abundant in northern seas. Goés found it in
the Arctic Sea at depths from 20 to 2500 metres. Although widely distributed, it is
especially common in the northern parts of the North Atlantic, as at Baffin’s Bay and
Smith’s Sound. In the southern hemisphere N. levigata has been recorded off
Patagonia and from the New Zealand area.
Nodosaria (Glandulina) rotundata, Reuss, sp. (Plate IIT, Figs. 20a, 206)
Glandulina rotundata, Reuss, 1849, Denkschr. d. k. Akad. Wiss. Wien, vol. i, p. 366,
Pl. XLVI, Fig. 2. Nodosaria (Glandulina) rotundata, Reuss, sp. H. B. Brady, 1884,
Rep. Chall., vol. ix, p. 491, Pl. LXI, Figs. 17-19. N. laevigata, VOrbigny. Goés,
1894, Kongl. Svenska Vetenskaps Akad. Handl., vol. xxv, p. 71, Pl. XII, Fig. 707.
This species is by far the commoner of the two Glanduline found in the Antarctic
washings, although usually it is the rarer. Our specimens show the various stages
from a simple chamber, indistinguishable from Lagena globosa, to the normal three- or
four-chambered adult form. The aperture is conspicuous, stellate, and wrinkled on
the surface; by oblique illumination under a low power the general surface is seen
to be delicately and sparsely striate. The distribution of this form is much the same
as that of the foregoing species.
Genus—Cristellaria, Lamarck, 1816
Cristellaria convergens, Bornemann (Plate III, Fig. 21)
Cristellaria convergens, Bornemann, 1855, Zeitschr. d. deutsch. geol. Gesellsch.,
Vol. vil, pyoot, Pl Xt. Mies 16, 17, HB. Brady, 1884, Rep. Chall., vol. ix, p. 546,
Pl EX Wiss. 65.7):
A specimen from the present material shows the typical characters of this
species. It is not an abundant form, but is fairly well distributed over the great
oceanic areas both in the north and south. Dr. Brady points out (loc. cit.) that the
best specimens have all been taken from very deep soundings.
Sub-family—PoLYMORPHININ &
Genus—Uvigerina, VOrbigny, 1826
Uvigerina angulosa, Williamson (Plate HI, Fig. 22)
Uvigerina angulosa, Williamson, 1858, Rec. Foram. Gt. Brit., p. 67, Pl. V, Fig. 140.
H. B. Brady, 1884, Rep. Chall., vol. ix, p. 576, Pl. LXXIV, Figs. 15-18. Chapman,
1909, Sub-Antarctic Islands of New Zealand, vol. 1, art. xv, p. 349.
* See also Goés (op. supra cit. p. 71, Pl. XHI, Fig. 703), a Psecadium-like form.
REPORT ON FORAMINIFERA AND OSTRACODA 33
This species is one of the most abundant of the smaller forms in the present series.
The tests are fairly typical, but the inflation of the last few chambers tends to obliterate
the usual feature of the trifacial compression of the test, at the oral extremity.
In the living condition U. angulosa is found at various depths in the N. and §.
Atlantic, the Mediterranean, the Indian Ocean, the N. and 8. Pacific, and the Southern
Ocean to the Antarctic ice barrier. It was an abundant species in the dredgings from
the sub-Antarctic islands of New Zealand. As a Pleistocene fossil it has been recorded
from Norway and the N.E. of Ireland.
Family—ROTALIID
Sub-family—RoraLun &
Genus—Discorbina, Parker and Jones, 1862
Discorbina vesicularis, Lamarck, sp. (Plate III, Fig. 23)
Discorbites vesicularis, Lamarck, 1804, Ann. du Muséum, vol. v, p- 183; vol. vil,
Pl. LXII, Fig. 7. Discorbina vesicularis, Lam., sp. H. B. Brady, 1884, Rep. Chall.,
vol. ix, p. 651, Pl. LXXXVII, Figs. 2a-2c.
One typical shell was found in the present deposit. As a living species it does
not appear to have been found farther south than the Victorian coast of
Australia. It inhabits water of moderate depths. It occurs as a Pleistocene fossil
in Norway.
Discorbina vilardeboana, d’Orbigny, sp. (Plate III, Fig. 24)
Rosalina vilardeboana, d’Orbigny, 1839, Foram. Amér. Mérid., p. 44, Pl. VI, Figs.
13-15. Discorbina vilardeboana, VOrb., sp. H. B. Brady, 1884, Rep. Chall., vol. ix,
p. 645, Pl. LXXXVI, Figs. 9-12; Pl. LXXXVIII, Fig. 2.
A well-formed test of this species having the characteristic brownish-pink colora-
tion of the initial series of chambers was found in the raised beach material. It is a
widely distributed form, and mainly affects shallow water. The closely related
D. araucana was recently recorded from the sub-Antarctic islands of New Zealand.
Genus—Truncatulina, @Orbigny, 1826
Truncatulina refulgens, Montfort, sp. (Plate III, Fig. 25)
Cibierdes refulgens, Montfort, 1808, Conch. Syst., vol. i, p. 122, 3le genre.
Truncatulina refulgens, Mont., sp. Egger, 1893, Abhand. k. bayer. Akad. Wiss., cl. ii,
vol. xvii, Abth. u, p. 401, Pl. XVI, Figs. 31-33. Chapman, 1909, Sub-Antarctic
Islands of New Zealand, vol. 1, art. xv, p. 357.
A common shell in the present deposit.
Among the many interesting forms of foraminifera which appear in the northern
and southern areas, but are absent from the tropics, this is a noteworthy example.
Its bathymetrical limits are wide. As a fossil it has been obtained from the Pliocene ;
and it occurs also in the Pleistocene deposits of Norway and the N.E. of Ireland.
Truncatulina lobatula. Walker and Jacob, sp. (Plate III, Fig. 26)
Nautilus lobatulus, Walker and Jacob, 1798, Adams’s Essays, Kanmacher’s ed.,
p. 642, Pl. XIV, Fig. 36. Truncatulina lobatula, W. and J., sp. Egger, 1893,
Abhandl. k. bayer. Akad. Wiss., cl. ii, vol. xvii, Abth. ii, p. 396, Pl. XVI, Figs. 1-3,
10-12. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. 1, art. xv, p. 358.
rE
It
34 REPORT ON FORAMINIFERA AND OSTRACODA
Four specimens of the above species occur in the present series. They are all
typical, stoutly built tests.
This is a widely distributed form, and is not restricted as to depth, although
usually inhabiting moderately shallow water.
Family—NUMMULINID
Sub-family—PoLYsTOMELLIN
Genus—Nonionina, d’Orbigny, 1826
Nonionina stelligera, VOrbigny (Plate II, Fig. 27)
Nonionina stelligera, d’Orbigny, 1839, Foram. Canaries, p. 128, Pl. III, Figs. 1, 2.
H. B. Brady, 1884, Rep. Chall., vol. ix, p. 728, Pl. CIX, Figs. 3-5.
It is extremely interesting to find this species occurrmg in the Antarctic, for it
is best known as an Arctic form. In the southern hemisphere it appears to be recorded
from only one area at three stations on the west coast of Patagonia, at depths of 125
to 245 fathoms.
EXPLANATION OF PLATES LIII
(All figures magnified 29 diameters)
PLATE I
Figure 1.—Biloculina depressa, d’Orbigny. A typical test: a, lateral aspect ;
b, peripheral aspect.
Figure 2.—B. depressa, d’Orbigny. A form with irregularly serrated peripheral
flange, and approaching Brady’s var. serrata. Lateral aspect.
FicurE 3.—B. depressa, d’Orbigny. A variety with narrow peripheral flange and a
salient aboral termination. Lateral aspect.
Ficure 4.—B. levis, Defrance sp. Lateral aspect.
Ficure 5.—B. sarsi, Schlumberger. a, Lateral aspect; 6, peripheral aspect.
PLATE II
Ficure 6.—B. elongata, d’Orbigny. Lateral aspect of a well-grown specimen.
Ficure 7.—Miliolina tricarinata, @Orbigny sp. a, Lateral aspect; b, oral aspect.
Figure 8.—Cornuspira involvens, Reuss sp. Lateral aspect.
Figure 9.—Bulimina seminuda, Terquem. a, Ventral aspect; 6, dorsal aspect.
Figure 10.—Vvirgulina schreibersiana, Czjzek. Lateral aspect.
Figure 11.—V. subsquamosa, Egger. Lateral aspect.
Figure 12.—Cassidulina oblonga, Reuss. a, Superior lateral aspect; 6, inferior and
oral aspect.
Figure 13.—C. parkeriana, H. B. Brady. Lateral and oral aspect.
Figure 14.—C. subglobosa, H. B. Brady. Ventral peripheral aspect.
Ficure 15.—Ehrenbergina pupa, d’Orbigny. a, Lateral aspect; 6, dorsal aspect.
Ficure 16.—E. serrata, Reuss. A full-grown test; ventral aspect.
FicurE 17.—#£. serrata, Reuss. An immature test.
35
36
FIGURE
FIGURE
FIGURE
FIGURE
‘FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
REPORT ON FORAMINIFERA AND OSTRACODA
PLATE III
18.—Lagena squamosa, Montagu sp. Lateral aspect.
19.—Nodosaria (Glandulina) levigata, @Orbigny. Lateral aspect.
20.—N. (Gl.) rotundata, Reuss, sp. a, Lateral aspect; b, oral aspect.
21.—Cristellaria convergens, Bornemann. Lateral aspect.
22.—Uvigerina angulosa, Williamson. Lateral aspect.
23.—Discorbina vesicularis, Lamarck, sp. Superior aspect.
24.—D. vilardeboana, d’Orbigny, sp. Superior aspect.
25.—Truncatulina refulgens, Montfort, sp. Inferior aspect.
26.—T. lobatula, Walker and Jacob, sp. A variety with faintly marked
sutures. Inferior aspect.
FIGURE
27.—Nonionina stelligera, d’Orbigny. Lateral aspect.
PLATE I
F.C. ad nat. del.
FoRAMINIFERA FROM Uptrurust Mups, S.E. oF Mount Larsen. 29 Diams.
(To face p. 36
PLATE II
Fic. 8
intel, Wil
Fic. 13
a b
Fic. 14 Fic. 15
F.C. ad nat. del.
FORAMINIFERA FROM UptHurst Mups, S.E. oF Mounr LARSEN. X 29 DIAMs.
PLATE III
Fic. 18
Kies) 22
BYGee
Fic. 27
Fic. 26
BGs)
F.C. ad nat. del.
FORAMINIFERA FROM Upturust Mups, S.E. oF Mounr LArseN. X 29 DIAms.
—"
- Pret
1
s
a
. ;
=| ae
a
a
ae
4m YF y
« -
4 : == 4
' van yebes Leak
bem ; i
—
ee
i f
aS
SECTION II
OSTRACODA
FROM UPTHRUST MUDS ABOVE THE DRYGALSKI GLACIER, SOUTH-
EAST OF MOUNT LARSEN
GENERAL REMARKS ON THE COLLECTION
From amongst the washed débris which yielded the Foraminifera of the accompanying
report, there were found a few ostracodal valves. They were all single, showing that
the connecting ligament of the hinge-line in every case had been fractured and
severed, and that deposition of sediment had not taken place before the carapace was
disunited by the action of local currents. This is often seen in recent soundings,
where, although at considerable depths, aided by the influence of currents, the valves are
frequently found separated.
Five species are herein described, one of which is new, whilst some others help to
elucidate already known but imperfectly understood species. They are comprised
in the genera Pontocypris, Cythere, Cytheropteron, and Cytherideis. All the previously
described species are Southern Oceanic forms, although one has also been recorded
from Torres Strait. One of the species, it is worth noting, shows close alliance with
fossil and recent Arctic and sub-Arctic species.
The evidence of these ostracoda as to their bathymetrical distribution is much
the same as that of the foraminifera; for they seem to indicate deposits, generally
speaking, of at least 100 fathoms, if not of greater depth.
DESCRIPTION OF THE OSTRACODA
Family—CYPRIDA
Genus—Pontocypris, G. O. Sars, 1865
Pontocypris subreniformis, G. 8. Brady (Pl. IV, Fig. 1)
Pontocypris-(?) subreniformis, G. 8. Brady, 1880, Rep. Chall., Zool., vol. 1, Pt. III,
p. 38, Pl. XV, Figs. 6a-6d (“‘ Pontocypris (2) subtriangularis, sp. n.”) on plate.
There is a slight confusion in the Challenger Report over what appear to be two
distinct forms. On p. 38 a Pontocypris is described under the name of P. (?) subrent-
formis,sp.n. The description there given corresponds with our Antarctic specimens.
Reference to Plate XV, Figs. 6a-6d, of the same Report, and given with the description,
will show that the species by mistake is there named Pontocypris (?) subtriangularis,
sp.n. Further, another figure, evidently ofa distinct species, but named Pontocypris (?)
subreniformis, is to be found on Plate VII, Figs. 5a-5d. The latter figures, which, by
the way, appear to be placed posterior extremity upwards, are closely related to a
fossil Bythocypris from the Wimmera borings in Victoria; and as Dr. G. 8. Brady
37
38 REPORT ON FORAMINIFERA AND OSTRACODA
makes reference to a possible alliance of his P. subreniformis with that genus (loc. cit.
p- 39), Figs. 5a-5d on Plate VII may be regarded as B. subreniformis, G. 8. Brady,
sp. (form figured but not described).
Three typical valves, one left and two right, of this rather delicate, thin-shelled
form occur in the present washings. They are very slightly larger than the type
recorded by Brady, our figured specimen having a length of °65 mm.
The earlier described specimens were from Simon’s Bay, S. Africa, 15 to 20
fathoms, and Port Jackson, Australia, 2 to 10 fathoms.
Family—CYTHERID
Genus—Cythere, Muller, 1785
Cythere foveolata, G. 8. Brady (Plate IV, Fig. 2)
Cythere foveolata, G. S. Brady, 1880, Rep. Chall., Zool., vol. i, Pt. II, p. 75,
Pl. XIII, Figs. 5a-5h.
It is interesting to note the occurrence of this species in previous soundings in
high latitudes. The localities of Dr. G. 8. Brady are off Christmas Harbour,
Kerguelen Island, at 120 fathoms; and off Heard Island at 75 fathoms. As allied
forms Brady cites an Arctic species, Cythere borealis, Brady, and C. edichilus, Brady,
a species from the Antwerp Crag (Lower Pliocene).
C. foveolata is the commonest form in the present series, and some of the immature
valves can be closely matched with Dr. Brady’s figure of (?) Cytheropteron angustatum,*
a form which that author found at Kerguelen Island and Torres Strait; and of which
he remarks, “‘ Possibly the genus Cythere might have been a more fitting receptacle
in this case, but from a few detached valves only it is not easy to arrive at an accurate
conclusion” (loc. cit. p. 137).
Cythere parallelogramma, G. 8. Brady (Plate IV, Fig. 3)
Cythere parallelogramma, G. S. Brady, 1880, Rep. Chall., Zool., vol. i, Pt. II,
p. 82, Pl. XV, Figs. la-le.
The only locality recorded for this species up to the present is Prince Edward
Island, Southern Ocean, from 50-150 fathoms.
Two left valves, in splendid condition, of female specimens.
Genus—Cytheropteron, G. O. Sars, 1865
Cytheropteron antarcticum, sp. n. (Plate IV, Figs. 4 a, 6)
Desecription.—Valve seen from the side, subrhomboidal; highest in the middle.
Height equal to about three-fifths of the length. Anterior border truncately rounded
above, sharply curved below. Dorsal line strongly arched and rapidly sloping
backward to meet the subacute posterior end. Ventral edge sinuous and moderately
curved. The anterior surface of valve slopes upward from the antero-dorsal region
towards the alar promimence, the latter being very pronounced and ending in a
moderately sharp pot. The surface of the slope along the alar-dorsal area is relieved
with irregular, sinuous, and curvilinear excavations. Just beneath the alar beak
a small pointed prominence occurs. Edge view of carapace rhomboidal, with acute
terminations.
* Rep. Chall., Zool., vol. i, Pt. III, 1889, p. 187, Pl. XXXIV, Figs. 5a—5b.
REPORT ON FORAMINIFERA AND OSTRACODA 39
Measurements.—Length, *67 mm.; height, ‘41 mm.; thickness of carapace,
*52 mm.
Observations.—The general outline of this species is suggestive of C. abyssorum,
G. 8. Brady.* There are, however, marked specific differences in the present form
which prevent any reference to that species. The greater relative length; the evenly
sloping surface of the alar prolongation; the relatively longer posterior extremity ;
and the absence of any superficial foveolation, all combine to render it distinct.
Type specimen, a right valve.
Genus—Cytherideis, Rupert Jones, 1856
Cytherideis levata, G. 8. Brady (Plate IV, Fig. 5)
Cytherideis levata, G. S. Brady, 1880, Rep. Chall., Zool., vol. i, Pt. Il, p. 146,
Pl. V, Figs. 5a-5d; Pl. XXXV, Figs. 6a-6d.
We have in the present series two typical valves of this delicate-shelled species.
On both examples there are peculiar elongate and contorted markings, seen through
the translucent shell, and probably due to remains of visceral attachments within
the valves.
This species was dredged by the Challenger off Heard Island, Southern Ocean,
from mud, at 75 fathoms. Dr. Brady remarks that the specimens were “ very few”
and seem to be all empty shells.”
* Rep. Chall., Zool., vol. i, Pt. III, 1880, p. 138, Pl. XXXIV, Figs. 3a-d.
EXPLANATION OF PLATE IV
(All figures magnified 29 diameters)
Ficure 1.—Pontocypris subreniformis, G. S. Brady. A right valve.
Ficure 2.—Cythere foveolata, G. 8. Brady. A right valve.
Figure 3.—Cythere parallelogramma, G. 8. Brady. A left valve.
Figure 4.—Cytheropteron antarcticum, sp. n. Right valve.
Ficure 5.—Cytherideis levata, G. 8. Brady. A right valve.
40
PLATE IV
Hixelo, 2)
Fic. 4
F.C. ad nat. del.
OsrrRacopDA rRoM Uprurust Mups, S.E. or Mount LARSEN. < 29 Diam.
[To face p. 40
SECTION III
FORAMINIFERA
FROM ELEVATED DEPOSITS ON THE SLOPES OF MOUNT EREBUS,
NEAR CAPE ROYDS
GENERAL REMARKS ON THE COLLECTION
Tur Foraminifera here described are from some elevated deposits obtained from
two localities on the slopes of Mount Erebus at 160 feet above sea-level.
Locality 1.—This deposit is composed chiefly of dark volcanic sand with
Serpule and a few foraminifera and echinoid spmes; near Back-Door Bay, about
three-quarters of a mile from Cape Royds.
Locality 2.—This deposit contains, with abundant mollusca, polyzoa (Cellaria
spp. and other genera), ostracoda, and foraminifera, some echinoid test-fragments
and spines, and numerous siliceous sponge-spicules (tetractinellid); about one and a
half miles from Cape Royds towards Cape Barne.
The last-named locality yielded all the specimens of Ostracoda, and the main
portion of the Foraminifera of these two Reports. The valves of the ostracoda were
exceptionally well preserved, and must have been floated together and covered up
by very gentle sedimentation.
Of the twenty-two species and varieties of Foraminifera here enumerated, twelve
are common also to the raised beach deposit south-east of Mount Larsen. They are:
Biloculina elongata, Cornuspira involvens, Bulimina seminuda, Cassidulina subglobosa,
C. parkeriana, C. oblonga, Ehrenbergina serrata, Nodosaria (Gl.) laevigata, N. (Gl.)
rotundata, Uvigerina angulosa, Truncatulina refulgens, and T. lobatula.
Judging from the general foraminiferal fauna of the Mount Erebus elevated
deposits, they were also formed in moderately deep water, like the preceding series
from south-east of Mount Larsen—viz. at or near 100 fathoms. The presence of many
delicate-shelled Ostracoda in the material from Locality 2 indicates, to my mind, a
decided clarity of conditions, as distinguished from the more silty or terrigenous
deposit of the sample from south-east of Mount Larsen.
DESCRIPTION OF THE FORAMINIFERA
Family—MILIOLIDA
Sub-family—MiILioLininz&
Genus—Bvrloculina, d’Orbigny, 1826
Biloculina elongata, d’Orbigny
(For references see previous Report)
One typical specimen found, nearly equalling in size the large forms here figured
from the upthrust muds south-east of Mount Larsen.
Loc. No. 2.
II 41 EF
AQ REPORT ON FORAMINIFERA AND OSTRACODA
Biloculina bradi, Schlumberger, var. denticulata, Brady
(Plate V, Fig. 1)
B. ringens, Lam., var. denticulata, Brady, 1884, Rep. Chall., vol. ix, p. 148, Pl. IT,
Figs. 4, 5. B. bradiz, Schl., var. denticulata, Brady, Chapman, 1909, Sub-Antarctic
Islands of New Zealand, vol. i, art. xv, p. 315, Pl. XIII, Fig. 2.
Two tests of this variety, closely resembling the recently figured example from
north of Auckland Island, New Zealand, at 85 fathoms, occurs in the floatings of the
Mount Erebus material.
Loc. No. 2.
Biloculina irregularis, @Orbigny (Plate V, Fig. 2)
B. irregularis, V@Orbigny, 1839, Foram. Amér. Meérid., p. 67, Pl. VIII, Figs. 22-24.
Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 295, Pl. XLI, Fig. 3. Chapman, 1909,
Rep. Sub-Antaretic Islands of New Zealand, vol. i, art. xv, p. 317.
The present examples are of small size. In the latter feature they agree with the
sub-Antarctic specimens dredged twenty miles north of AucklandIsland at 85 fathoms.
Loc. No. 1, very rare; No. 2, frequent.
Genus—WMiliolina, Williamson, 1858
Miliolina circularis, Bornemann, sp. (Plate V, Fig..3)
Triloculina circularis, Bornemann, 1858, Zeitschr. d. deutsch. geol. Gesell., vol. vii,
p- 349; Pl. XIX, Fig. 4. Muliolina circularis, Born., sp., Millett, 1898, Jowrn. R.
Micr, Soc., p. 499, Pl. XI, Figs. 1-3. Chapman, 1909, Sub-Antarctic Islands of New
Zealand, vol. i, art. xv, p. 318.
This species is not common in the living condition, as regards the Southern Ocean.
It wasa characteristic form in the dredgings amongst the sub-Antarctic islands of New
‘eae It ranges into moderate depths, keeping generally near the 100-fathom
ine.
ale small, sub-rotund varieties, having the typical broad aperture, were found.
oc. No. 2.
Sub-family—HaveriIninm&
Genus—Planispirina, Seguenza, 1880
Planispirina bucculenta, Brady, sp. (Plate V, Fig. 4)
Miliolina bucculenta, Brady, 1884, Rep. Chall., vol. ix, p. 170, Pl. CXIV, Figs. 3a,
3b. Planispirina bucculenta, Brady, sp., Schlumberger, 1892, Mém. Soc. Zool. France,
vol. v, p. 194, Pl. VIII, Figs. 6, 7; woodcuts, Figs. 2-4. Chapman, 1909, Sub-
Antarctic Islands of New Zealand, vol. i, art. xv, p. 324, Pl. XIV, Fig. 2.
The gradual extension of the area affected by this striking species is further
augmented by its occurrence here in the Antarctic regions. At first known only from
the Arctic seas and the North Atlantic, it has since been found off Australia; between
there and New Amsterdam Island, and lately in the sub-Antarctic islands of New
Zealand. In the northern hemisphere it is a fairly deep water species. Numerous
specimens occurred in the washed material from the slopes of Mount Erebus, 160 feet
above sea-level.
Loc. No. 2,
REPORT ON FORAMINIFERA AND OSTRACODA 43
Planispirina bucculenta, var. placentiformis, Brady, var. (Plate V, Fig. 5)
Miliolina bucculenta, var. placentiformis, Brady, 1884, Rep. Chall., vol. ix, p. 171,
PVE, Bios 152. Planispirina bucculenta, var. placentiformis, Brady, Chapman,
1909, Sub-Antaretic Islands of New Zealand, vol. i, art. xv, p. 324,
The present occurrence, in a pleistocene deposit, makes the fourth locality for this
variety; the previous records being: Culebra Island, West Indies; Kerguelen
Island; and the sub-Antarctic islands of New Zealand.
The variety is not so common as the type form in this deposit.
Loc. No. 2.
Sub-family—PENEROPLIDINE
Genus—Cornuspira, Schultze, 1854
Cornuspira involvens, Reuss, sp.
(For references see previous Report)
This species is an important form in the present series, being fairly common and
of maximum size, measuring as much as 1°7 mm. in diameter.* The test, in later
stages of growth, tends to form a wider tube, and has a more or less corrugated shell-
surface. All the specimens noted belong to the microspheric stage, as does the one
figured from the raised beach south-east of Mount Larsen.
Loc. No. 2.
Family—TEXTULARIID
Sub-family—BuLmmniIn&
Genus—Bulimina, d’Orbigny, 1826
Bulimina seminuda, Terquem (Plate V, Fig. 6)
(For references see previous Report)
This species occurs in both of the elevated deposits of the present Report. It
is commoner and much better developed in that from locality No. 1, which consists
largely of volcanic sand and serpula fragments.
Sub-family—CassIDULININZE
Genus—Cassidulina, V@Orbigny, 1826
Cassidulina oblonga, Reuss
(For references see previous Report)
As in the elevated material from above the Drygalski Glacier, this species is
moderately common in the present deposit.
Loc. Nos. 1 and 2.
Cassidulina parkeriana, Brady
(For references see previous Report)
This form is here very common, as in the previously reported material from above
the Drygalski Glacier, south-east of Mount Larsen.
Loc. Nos. 1 and 2.
* Dr. H. B. Brady remarks that this species seldom exceeds 1°26 mm. in diameter.
44 REPORT ON FORAMINIFERA AND OSTRACODA
Cassidulina subglobosa, Brady
(For references see previous Report)
This is a rare form in the present deposit. Loc. No. 2.
Genus—Ehrenbergina, Reuss, 1849
Ehrenbergina serrata, Reuss
(For references see previous Report)
Moderately common in the present deposit. Loc. Nos. 1 and 2.
Family—LAGENID A
Sub-family—N oposaRuINz
Genus—WNodosaria, Lamarck, 1816
Sub-genus—Glandulina, d’Orbigny, 1826
Nodosaria (Glandulina) levigata, dOrbigny
(For references see previous Report)
Only one example was found in the present deposit. Loc. No. 2.
Nodosaria (Glandulina) rotundata, Reuss, sp.
(For references see previous Report)
Several examples found in the elevated material from the slopes of Mount Erebus.
Loc. No. 2.
Genus—Cristellaria, Lamarck, 1816
Cristellaria crepidula, Fichtel and Moll, sp. (Plate V, Fig. 7)
Nautilus crepidula, Fichtel and Moll, 1798, Test. Mier., p. 107, Pl. XIX, Figs. g—.
Cristellaria crepidula, F. and M., sp., Brady, 1884, Rep. Chall., vol. 1x, p. 542.
Pl. LXVII, Figs. 17, 19, 20; Pl. LXVIII, Figs. 1, 2. Chapman, 1909, Sub-Antarctic
Islands of New Zealand, vol. i, art. xv, p. 343.
A fragmentary specimen was found, showing the initial half of the test. It has
the outline of C. lata, Cornuel, sp., but isnot so compressed. It was lately recorded
fromthe sub-Antarctic islands of New Zealand, where it occurred with some frequency.
Loc. No. 1.
Cristellaria gibba, d’Orbigny (Plate V, Fig. 8)
Cristellaria gibba, d’Orbigny, 1839, Foram. Cuba, p. 63, Pl. VII, Figs. 20, 21.
H. B. Brady, 1884, Rep. Chall., vol. ix, p. 546, Pl. LXIX, Figs. 8, 9. Chapman,
1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv, p. 344.
This elongate and compressed modification of C. rotulata has been recorded from
the South Pacific by Brady, off Western Australia by Egger, and latterly by the writer,
from the sub-Antarctic islands of New Zealand (60-85 fathoms).
Loc. No. 2.
Sub-family—PoLYMORPHININE
Genus—Uvigerina, d’Orbigny, 1826
Uvigerina angulosa, Williamson
(For references see previous Report)
Two specimens found in the present elevated deposit.
REPORT ON FORAMINIFERA AND OSTRACODA 45
Family—GLOBIGERINIDA
Genus—Pullenia, Parker and Jones, 1862
Pullenia quinqueloba, Reuss, sp. (Plate V, Fig. 9)
Nonionina quinqueloba, Reuss, 1851, Zeitschr. d. deutsch. geol. Gesell., vol. iii, p. 47,
Pl. V, Figs. 31a, 31b. Pullenia quinqueloba, Reuss, sp., Brady, 1884, Rep. Chall.,
vol. ix, p. 617, Pl. LX XXIV, Figs. 14, 15. Flint, 1899, Rep. U.S. Nat. Mus. for
1897, p. 324, Pl. LXX, Fig. 5. Chapman, 1906, Trans. and Proc. N. Zealand Inst.,
vol. xxxviil, p. 101.
This species appears to be more generally met with in soundings from the northern
hemisphere ; but it is also fairly well distributed in the Southern Ocean. It occurs
in the dredgings from Great Barrier Island, off New Zealand, but was not recorded
from the sub-Antarctic islands.
Two typical examples were found in the elevated deposit from the slopes of
Mount Erebus.
Loc. Nos. 1 and 2.
Family—ROTALIID
Sub-family—RoraLinz
Genus—Truncatulina, d’Orbigny, 1826
Truncatulina refulgens, Montfort, sp.
(For references see previous Report)
It is interesting to note that this species is rare in these deposits, whereas in the
elevated material south-east of Mount Larsen it is common; whilst in the case
of the next recorded form, 7’. lobatula, the reverse obtains. This points to the inter-
relation of the two forms, probably influenced by bottom conditions rather than
depth, as they both have an unrestricted range. In the one case, from near Mount
Larsen, the deposit being silty, the high conical form flourishes; in the other, where
the deposit is cleaner, sandy, and fragmentary, the low, plano-convex shell is the
prevailmg form.
Loc. Nos. 1 and 2.
Truncatulina lobatula, Walker and Jacob, sp.
(For references see previous Report)
This species is the commonest form in these deposits. It shows some variability,
in that the usually flat base tends to become concave in one direction, as though it
were endeavouring to build on a cylindrical surface. No attached examples, however,
were found.
Loc. Nos. 1 and 2.
Truncatulina haidingeri, dOrbigny, sp. (Plate V, Fig. 10)
Rotalina haidingert, dOrbigny, 1846, Foram. Foss. Vienne, p. 154, Pl. VIII,
Figs. 7-9. Truncatulina (Rotalina) haidingeri, d’Orb., sp., Egger, 1893, Abhandl. k.
bayer. Akad. Wiss., cl. ii, vol. xviii, p. 401, Pl. XVI, Figs. 25-27. T. haidingeri,
d’Orb., sp., Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv,
. 359.
2 One example found. Typical specimens are not at all common in recent soundings.
This species has previously occurred at a few stations in the Southern Ocean. It has
46 REPORT ON FORAMINIFERA AND OSTRACODA
lately been recorded from the Great Barrier Island, and off the Snares, sub-Antarctic
islands of New Zealand.
Loc. No. 1.
Genus—Pulvinulina, Parker and Jones, 1862
Pulvinulina oblonga, Williamson, sp. (Plate V, Fig. 11)
Rotalina oblonga, Williamson, 1858, Rec. Foram. Gt. Brit., p. 51, Pl. IV, Figs. 98-
100. Pulvinulina oblonga, Will, sp., Brady, 1884, Rep. Chall., vol. ix, p. 688,
Pl. CVI, Figs. 4a—4e.
This species has occurred off the Cape of Good Hope and in the South Pacific
(17-275 fathoms), amongst other localities, the majority of which are in the northern
hemisphere.
Loc. No. 1.
PLATE V
EXPLANATION OF PLATE V
(All figures magnified 29 diameters)
Figure 1.—Biloculina bradii, Schlumberger, var. denticulata, Brady. Front or oral
aspect. Elevated deposit, between C. Royds and C. Barne.
Ficure 2.—B. irregularis, d’Orbigny. Oral aspect. Deposit, between C. Royds and
C. Barne.
Ficure 3.—Miliolina circularis, Born., sp. Lateral aspect. Deposit, between C.
Royds and C. Barne.
Figure 4.—Planispirina bucculenta, Brady. Oral aspect of a specimen with a
siliceous sponge-spicule intergrown with the test. Deposit, between C. Royds
and C. Barne.
Ficure 5.—P. bucculenta, var. placentiformis, Brady. Lateral aspect. Deposit,
between C. Royds and C. Barne.
Ficure 6.—Bulimina seminuda, Terquem. Dorsal aspect of a full-grown example.
Deposit, near C. Royds.
Ficure 7.—Cristellaria crepidula, Ficht. and Mboll., sp. Lateral aspect. Deposit,
near C. Royds.
ee 8.—C. gibba, d’Orbigny. Lateral aspect. Deposit, between C. Royds and C.
arne.
Ficure 9.—Pullenia quinqueloba, Reuss, sp. Deposit, near C. Royds.
Ficure 10.—Pulvinulina haidingeri, dOrb., sp. 4, Peripheral aspect; 6, inferior
aspect. Deposit, near C. Royds.
Ficure 11.—P. oblonga, Will., sp. Superior aspect. Deposit, near C. Royds.
48
PLATE V
Hire 10)
B.C. ad nat. del.
FORAMINIFERA FROM ELEVATED Deposits, SLOPES OF Mount ErreBUS, NEAR CAPE Royps.
< 29 DiaMs.
[To face p. 48
SECTION IV
OSTRACODA
FROM ELEVATED DEPOSITS ON THE SLOPES OF MOUNT EREBUS,
BETWEEN CAPE ROYDS AND CAPE BARNE
GENERAL REMARKS ON THE COLLECTION
ALL the Ostracoda here recorded were obtained from some moderately fine washings
floated from the molluscan siftings examined by Mr. Chas. Hedley. The material
was obtained from the deposit found 160 feet up the slopes of Mount Erebus, about
one mile and a half from Cape Royds towards Cape Barne. The specimens are very
abundant, but belong to few species. They range from 20 fathoms in the case of
Cytherura costellata to 1425 fathoms in Bairdia victriz. The occurrence of B. victria
tends to show a limiting depth for the deposit of rather more than 100 fathoms, since
the least depth for that species hitherto recorded is 120 fathoms. There are eight
species in this series, two of which are new forms. They belong to the genera Bairdia,
Cythere, Loxoconcha, Xestoleberis, and Cytherura. In point of abundance Cythere
parallelogramma comes first, the next in order being C. polytrema and C. normani ;
the remainder being somewhat, or altogether, rare. All the previously described
species are either known from, or allied to forms of, the Southern Ocean.
DESCRIPTION OF THE OSTRACODA
Family—BAIRDIIDA
Genus—Bairdia, McCoy, 1844
Bairdia victriz, G. 8. Brady (Plate VI, Fig. 1)
Bairdia victriz, G. 8. Brady 1867, Les Fonds de la Mer, vol. i, p. 1525 Pl. XVaE.
Figs. 17, 18. Idem, 1880, Rep. Chall., Zool., vol. i, Pt. III, p. 56, Pl. X, Figs. 5a—-5d.
Some remarkably fine valves occur in the present series. The species has some
resemblance to B. amygdaloides, which is found as far south as Bass Strait, but the
posterior extremity is rounded off instead of tapering to a point. It has a wide range:
from the West Indies to Kerguelen Island, and thence to Sydney. It inhabits
“chiefly water of a considerable depth” (G. S. B.).
Family—CYTHERIDA
Genus—Cythere, Muller, 1785
Cythere foveolata, G. 8. Brady
(For references see previous Report)
Two valves of this species occur here. It has already been noted from the upthrust
muds south-east of Mount Larsen, in which deposit it was rather abundant.
Il 49 G
50 REPORT ON FORAMINIFERA AND OSTRACODA
Cythere parallelogramma, G. 8. Brady
(For references see previous Report)
This species is here abundant, whilst in the raised beach deposit south-east of
Mount Larsen it was a rare form.
Cythere norman, G. 8. Brady (Plate VI, Fig. 2)
Cythere normani, G. S. Brady, 1865, Trans. Zool. Soc. Lond., vol. v, p. 379,
Pl. LXI, Figs. 5a-5d. Idem, 1880, Rep. Chall., Zool., vol. i, Pt. II, p. 101, Pl. XVII,
Figs. 3a-3d, and (?) Pl. XXVI, Figs. 4a—46.
Dr. Stewardson Brady found this species in the Challenger collection between
Kerguelen Island and Heard Island, Southern Ocean, at 150 fathoms; and some
stouter examples, which he doubtfully referred to the same species, off the west coast
of South America, at 1825 fathoms. The latter examples have some light thrown
upon them through the present series. I am led to think that the South American
specimens belong to the same form; they are of heavier build, with a well-marked
subcentral knob on the surface of each valve. In the latter feature this species
approaches C. parallelogramma, from which it differs, however, in being stouter and
anteriorly broader. The species is a very variable one, judging by Brady’s original
figures of the Abrohlos Bank specimens.
The present examples are of finer texture, the reticulated surface being compara-
tively delicate, and the anterior and posterior spmulose border more densely armed
with fine prickles. The subcentral boss is present in all the specimens, and the sub-
marginal ridge of the ventral border is sharp and thin.
Cythere polytrema, G. S. Brady (Plate VI, Fig. 3)
Cythere polytrema, G. S. Brady, Trans. Zool. Soc. Lond., 1878, vol. x, p. 393,
Pl. LXVI, Figs. la-1d. Idem, 1880, Rep. Chall., Zool., vol. i, Pt. III, p. 87, Pl. XXT,
Figs. 5a—5h.
This species is represented in the present series by a fair number of valves. They
are in a fine state of preservation, and the spines at either extremities are exceptionally
long and slender. It has been previously recorded as a fossil from the Antwerp Crag
(Lower Pliocene) of Belgium; and in recent soundings by the Challenger at 50-150
fathoms off Prince Edward Island, Southern Ocean.
Genus—Lozoconcha, G. O. Sars, 1865
Loxoconcha mawsoni, sp. n. (Plate VI, Figs. 4a, 4b)
Description.—Carapace oblong, tumid. Valve seen from the side, peach-stone
shaped, but unusually produced anteriorly. Dorsal margin roundly and evenly
curved; ventral strongly convex in middle, sinuously excavated near the anterior,
and obliquely rounded at the posterior extremity, where it meets the blunt posterior
process. Edge view of carapace subovate, slightly compressed towards the extremities,
especially anteriorly ; greatest thickness just below the median line. Surface polished,
and relieved by a distant, vertical, linear series of elongate shallow pits.
Measurements.—Length, ‘76 mm.; width, -45 mm.; thickness of carapace, 34 mm.
A ffinities.—The nearest related form to this distinct species is Loaxoconcha honolu-
liensis, G. S. Brady,* a coral reef form from Honolulu. In shape the latter is broader
* Rep. Chall., Zool., vol. i, Pt. III, 1880, p. 117, Pl. XXVIII, Figs. 6a-6f.
REPORT ON FORAMINIFERA AND OSTRACODA 51
along the median line, not so much produced anteriorly, and with greater compression
of the extremities. Its ornament, moreover, consists of scattered circular pittings
without linear arrangement.
Genus—Xestoleberis, G. O. Sars, 1865
Xestoleberis davidiana, Chapman (Plate VI, Figs. 5a—-5e, 6)
Xestoleberis davidiana, Chapman, 1915, Zool. Results, “ Endeavour,’ vol. iii,
Ptoly ps 45.
Description.—Carapace in side view, semiovate, bluntly pointed in front and
behind; back rounded, slightly angulated at the summit; ventral border gently
concave, edge rounded, ventral surface excavate. Edge view, compressed ovate.
End view conical, with rounded sides. Surface of shell more or less numerously
pitted, each pit or group of pits surrounded by a white spot; probably armed with
fine bristles (as in X. setegera) in the living state. A few valves of narrower build are
present, one of which is figured; they are probably referable to male specimens.
Measurements.—Length of type specimen, *48 mm.; greatest thickness of carapace,
°3 mm.; height, 3 mm.
Observations.—At first sight this species reminds us of X. setigera, G. 8S. Brady,*
both in the narrow side view of the carapace and the punctate ornament. The latter,
however, in X. setigera is distinctly papillate. This present species is distinguished
by the subacute extremities in side view and the pointed dorsal area of the end view.
X. davidiana, whilst related to X. setigera, also a southern form, may be regarded
as distinct on the strength of the above characters, which are constant throughout
the numerous specimens occurring in the elevated deposit from the slopes of
Mount Erebus.
Genus—Cytherura, G. O. Sars, 1865
Cytherura costellata, G. 8. Brady (Plate VI, Fig. 7)
Cytherura costellata, G. 8. Brady, 1880, Rep. Chall., Zool., vol. i, Pt. II, p. 134,
Pl. XXXII, Figs. 7a-7d.
A single valve of this pretty little species was found in the elevated material.
It measures ‘5 mm. in length, exactly that of the type figured by Dr. G. 8. Brady,
who obtained his specimens from Balfour Bay, Kerguelen Island, in 20-50 fathoms.
This occurrence, therefore, is the second recorded for the species.
* Rep. Chall., Zool., vol. i, Pt. III, 1880, p. 125, Pl. XX XI, Figs. 2a—d, 3a-c.
EXPLANATION OF PLATE VI
(All figures magnified 29 diameters)
Ficure 1.—Bairdia victriz, G. 8. Brady. Left valve.
Figure 2.—Cythere normani, G. 8. Brady. Right valve.
Ficure 3.—C. polytrema, G. 8. Brady. Right valve.
Figure 4.—Loxoconcha mawsoni, sp. n. Left valve: a, lateral aspect; b, edge view.
Ficure 5.—Xestoleberis davidiana, Chapman. Type specimen. Left valve: a, lateral
aspect ; 6, ventral edge view; c, front end view.
Ficure 6.—X. davidiana, sp. n. Paratype. Right valve; probably male example.
Ficure 7.—Cytherura costellata, G. 8. Brady. Right valve.
PLATE VI
F.C. ad. nat. del.
OstRAcODA FROM ELEVATED Drposrrs, SLopEs oF Mount Eresus, ABour 1) MILe
FROM C. Royps Trowarps C. Barne. 29 DIAM.
[To face p. 52
PART II
REPORT ON THE FORAMINIFERA AND
OSTRACODA
OUT OF MARINE MUDS FROM SOUNDINGS IN
THE ROSS SEA
SOUNDINGS TAKEN BY CAPTAIN J. K. DAVIS, S.Y. NIMROD
(With Six Plates)
BY
FREDERICK CHAPMAN, A.L.S., F.R.M.S.
Palxontologist to the National Museum, Melbourne
CONTENTS
PAGE
INTRODUCTION 55
SCHEDULE OF SOUNDINGS. 55
DESCRIPTION OF THE FORAMINIFERA 57
DESCRIPTION OF THE OSTRACODA 71
SUMMARY OF RESULTS 75
BATHYMETRICAL DISTRIBUTION OF THE MICROZOA 76
78
EXPLANATION OF THE PLATES
ro
INTRODUCTION
Tue following report is based on muds collected by Captain J. K. Davis, 8.Y. Nimrod,
from soundings taken in the Ross Sea. The material was courteously placed in my
hands by Professor T. W. Edgeworth David, C.M.G., D.Sc., F.R.S. These soundings
have yielded most excellent results, not so much on account of the variety of specific
forms they contain, as for the information afforded regarding the approximate depths
and habitats of the Raised Beach material previously described, which occurred at
heights of 20 and 160 feet above sea-level. They also furnish some further interesting
data regarding the extension of Arctic species into Antarctic regions,* reference to
which will be made in the summary.
Fifteen samples of soundings were examined, and from only two of these were
calcareous organisms absent. The range of depth in the samples is from 110 to 655
fathoms. The general nature of the soundings suggests an old shore-line which is
undergoing much wear and tear, for the material constituting the deposits is in the
main terrigenous, consisting of gritty diatomaceous ooze, green muds, and volcanic
sand. Asa matter of convenience the soundings are here grouped in rotation according
to depth, from above downwards.
SCHEDULE OF SOUNDINGS ARRANGED IN ORDER OF DEPTH
SY. NIMROD J.K. DAVIS, Commander
| Longitude General Contents
Date Latitude Nature of Sounding
|Fathoms
2.1.09 | 76°56’ S. | A few diatoms (Coscinodiscus, etc.).
| Foraminifera frequent. Sponge
spicules abundant. Polyzoa.
164°51’E.| 110 | Green terrigenous
| mud and pebbles
| of (2) quartz fel-
S. 1164°55’ E. |
13.1.09 | 76°55’ S. | 164°45’ E.
12.2.09 |MeMurdo Sound,
one mile from the
outer end of Glacier
Tongue, northern
side.
* See also ante, ‘ Report on the
Shores of the Ross Sea.”
site.
Black mud.
Green mud.
Volcanic mud and
stones.
55
Ostracoda.
Foraminifera, as Cassidulina and
Uvigerina, abundant. A few
Radiolaria and Sponge spicules.
Diatomaceze (Coscinodiscus, etc.).
Arenaceous Foraminifera (Sac-
cammina and Pelosina ; numer-
ous hyaline forms in finer portion.
Polyzoa.
Diatomacese (Coscinodiscus, etc.).
Foraminifera common. Sponge
spicules. Echinoid _ spines.
Ostracoda.
Foraminifera and Ostracoda from Elevated Deposits on the
56 REPORT ON FORAMINIFERA AND OSTRACODA
SCHEDULE OF SOUNDINGS ARRANGED IN ORDER OF DEPTH (continued)
No. Date Latitude Longitude Nature of Sounding General Contents
athens
ae ee |e ee |
Bie | ail ROON idieslISSaIGDS De Beal alial Dark peers Diatomaceze (Coscinodiscus, etc.).
Few Foraminifera. Sponge
spicules. Ostracoda.
6 | 10.1.09 | 77°12’S. | 164° 36’E.} 181 | Black mud & sand,| Few diatomaceze (Coscinodiscus,
with pebbles of | etc.). No Foraminifera. A
granitic rock. few Radiolaria.
7 | 11.1.09 | Information missing | 225 | Black terrigenous |} Diatomaceze (Coscinodiscus, etc.).
mud and sand. Foraminifera. Sponge spicules.
Ostracoda.
8 | 15.1.09 | 76°49’S. [163°24’ E.)} 853 | Green terrigenous | Diatomaceze (Coscinodiscus, etc.)
mud, abundant. Foraminifera numer-
ous. Hchinoid spines. Polyzoa
(Cellaria). Pteropoda (Vaginella).
Ostracoda.
9 | 15.1.09 | 76°47’S. |163°22’E.] 360 | Green terrigenous | Diatomaceze (Coscinodiscus, etc.)
mud, abundant. A few Arenaceous
Foraminifera and Radiolaria.
10 | 15.1.09 | 76°48’ S.|163°20’ E.| 372 |Green terrigenous | Diatomaceze (Coscinodiscus, etc.).
(label mud. Radiolaria. Foraminifera ex-
torn) cessively minute and = un-
developed.
11 5.1.09 | 77°25’ S.|] 166°5’ E.| 459 | Dark, gritty, ter- | Diatomaceze (Coscinodiscus, etc.).
rigenous mud. Radiolaria. No Foraminifera.
12 5.1.09 | 77° 1643'S. }165°55’ E.| 460 | Green terrigenous | Diatomacez (Coscinodiscus, etc.)
mud, abundant. Radiolaria common.
Arenaceous Foraminifera.
Sponge spicules.
13 | 14.1.09 | 76°46’ S. |163°26’ E.| 462 | Green terrigenous | Diatomaceze (Coscinodiscus, etc.)
6 A.M. mud. abundant. Radiolaria frequent.
Arenaceous Foraminifera.
Sponge spicules common. Also
a few gritty particles of quartz
and volcanic débris.
14 4.1.09 |Cape Bird (Ross
Island) bearing | 472 | Terrigenous mud | Diatomacese (Coscinodiscus, etc.)
N. 79° H. (true). with pebbles. abundant. Radiolaria. Arena-
Distance, 44 miles. ceous Foraminifera.
|
15 5.2.09 | Relief Harbour, N. | 655 | Green terrigenous | Diatomaceze (Coscinodiscus, etc.)
Drygalski Glacier, | mud. | abundant. Arenaceous Fora-
about 20 miles off minifera rare.
coast.
DESCRIPTION OF THE FORAMINIFERA
Family—MILIOLID
Sub-family— MinioLinin.&
Genus—Biloculina, d’Orbigny, 1826
Biloculina depressa, d’Orbigny (for references see previous Reports on Foraminifera
of Elevated Deposits).
Occurrence.—Sample No. 2, 113 fathoms, very rare.
Biloculina elongata, d’ Orbigny (for references see previous Reports on Foraminifera
of Elevated Deposits).
Occurrence.—Sample No. 2, 113 fathoms, very rare ; No. 3, 121 fathoms, frequent,
one of large size ; No. 4, 153 fathoms, rare ; No. 5, 171 fathoms, very rare.
Biloculina bradw, Schlumberger (Plate I, fig. 1).
Biloculina ringens, H. B. Brady (non Lamarck), 1884, Rep. Chall., vol. ix, p. 142,
pl. ui, fig. 7. B. bradyi, Schlumberger, 1891, Mem. Soc. Zool. France, vol. iv, p. 557,
pl. x, figs. 63-71 ; woodcuts 15-19. B. bradyi, Schlumberger, Chapman, 1907, Journ.
Linn. Soc. Lond., Zool., vol. xxx, p. 18, pl. i, figs. 7, 8. Idem, 1909, Sub-Antarctic
Islands of New Zealand, vol. i, art. xv, p. 314, pl. xin, fig. 1.
The distribution of this species is wide, and does not yet seem to be fully worked
out, on account of its having been confused with B. ringens, Lam. The localities
include the Gulf of Gascony, and the sub-Antarctic islands of New Zealand (off the
Snares, N. of Auckland Island, and N. of Enderby Island). It has also been recorded
as a Tertiary (Oligocene) fossil from Grice’s Creek, Port Phillip.
The only example found in the present soundings is a fine specimen measuring
3-75 nm. in length. A variety of this species, viz. denticulata, Brady, has been pre-
viously recorded from a raised beach at 160 feet, on the slopes of Mount Erebus, between
Cape Royds and Cape Barne.
Occurrence.—Sample No. 1, 110 fathoms, one specimen.
Biloculina wrreqularis, VW Orbigny (for references see previous Reports on Foraminifera
of Elevated Deposits).
Occurrence.—Sample No. 5, 171 fathoms, very rare ; No. 8, 353 fathoms, very rare.
Genus—Spiroloculina, d’Orbigny, 1826
Spiroloculina canaliculata, d’Orbigny (Plate I, fig. 2)
Spiroloculina canaliculata, d’Orbigny, 1846, Forum. Foss. Vienne, p. 269, pl. xvi,
figs. 10-12. SS. limbata, d’Orbigny (var.), H. B. Brady, 1884, Rep. Chall., vol. ix,
p. 150, pl. x, figs. 1, 2. S. canaliculata, d’Orbigny, Rupert Jones, 1895, Foram.
Craq. (Pal. Soc. Mon.), pt. ii, p. 108, pl. in, figs. 39, 40 ; woodcuts, figs. 3a, 6 ; Chapman,
1907, Journ. Linn. Soc. Lond., Zool., vol. xxx, p. 16, pl. i, figs. 20, 21.
57
58 REPORT ON FORAMINIFERA AND OSTRACODA
Dr. Brady’s figured examples came from the coast of Papua. Rupert Jones states
that it is ““not uncommon in the Mediterranean, in shallow and moderately deep
waters.” As a fossil it occurs in the Oligocene of Port Phillip (Kackeraboite Creek) ;
in the Miocene of the Vienna Basin and Malaga ; and in the Pliocene of Sutton, Suffolk,
England. Its present occurrence is therefore remarkable for its high latitude.
Occurrence.—Sample No. 8, 353 fathoms, very rare.
Genus—Miliolina, Williamson, 1858
Miliolina subrotunda, Montagu, sp., var. striata, var. nov. (Plate I, fig. 3)
Reference to type species.—Miliolina subrotunda, Montagu, sp., H. B. Brady, 1884,
Rep. Chall., vol. ix, p. 168, pl. v, figs. 10, 11.
The present example is a small, neat specimen ornamented with distinct strize
concentric with the curved outline of the shell. It calls to mind Brady’s M. circularis,
var. sublineata,* but the type of shell is that of M. subrotunda, both as to aperture and
contour.
Occurrence.—Sample No. 8, 353 fathoms, one specimen.
Miliolina vulgaris, d’Orbigny, sp. (Plate I, fig. 4)
Quinqueloculina vulgaris, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii, p. 302, No. 33.
Miliolina auberiana, d’Orbigny, sp., H. B. Brady, 1884, Rep. Chall., vol. ix, p. 162,
pl. v, figs. 8, 9. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art.
XV, p. 320.
Of cosmopolitan distribution, this species is here extended farther south than any
specimens hitherto recorded.
Occurrence.—Sample No. 8, 353 fathoms, one specimen.
Miliolina bicornis, Walker and Jacob, sp. (Plate I, fig. 5)
Serpula bicornis, Walker and Jacob, 1798, Adams’ Essays, Kanmacher’s ed.,
p. 633, pl. xiv, fig. 2. Triloculina brongniartii, d’Orbigny, 1826, Ann. Sci. Nat., vol.
vii, p. 300, No. 23. Miliolina bicornis, d’Orbigny, sp., H. B. Brady, 1884, vol. ix,
p. 171, pl. vi, figs. 9, 11, 12.
A very small, but otherwise well-marked and typical specimen. It is of great
interest to discover this species so far south, since it has been hitherto confined to
temperate and tropical waters. Hence the small size of the present example. The
depth is also a record, the Challenger finding it only as low as 120 fathoms.
Occurrence.—Sample No. 8, 353 fathoms, one specimen.
Miliolina agglutinans, d’Orbigny, sp. (Plate I, fig. 6)
Quinqueloculina agglutinans, d’Orbigny, 1839, Foram. Cuba, p. 168, pl. xii, figs.
11-13. Miliolina agglutinans, d’Orbigny, sp., H. B. Brady, 1884, Rep. Chall., vol.
ix, p. 180, pl. viii, figs. 6, 7. Chapman, 1907, Journ. Linn. Soc. Lond., Zool., vol. xxx,
p- 20, pl. u, fig. 36.
As might be expected, the majority of the miliolines in the fine, terrigenous soundings
of the Antarctic are mainly arenaceous forms, of which this is amongst the commonest.
Its southern distribution includes Cape of Good Hope, 150 fathoms; Prince Edward
* Rep. Chall., vol. ix, 1884, p. 169, pl. ix, figs. Ta-c.
REPORT ON FORAMINIFERA AND OSTRACODA 59
Island, 1900 fathoms ; and off Sydney, 410 fathoms. As a fossil this species has been
noted from the post-tertiary clays of Norway and the west of Scotland ; and it is fairly
common in the Balcombian clays of Port Philip and Muddy Creek, but rarer in the
Kalimnan of the latter locality. The present specimens are more neatly built than
usual, and the contours are rounder.
Occurrence.—Sample No. 7, 225 fathoms, very rare; No. 9, 360 fathoms, common ;
No. 12, 460 fathoms, very common; No. 13, 462 fathoms, common; No. 14, 472
fathoms, frequent.
Miliolina oblonga, Montagu, sp., var. arenacea, var. nov. (Plate I, fig. 7)
Reference to type species.—Vermiculum oblongum, Montagu, 1803, Test. Brit.,
p. 522, pl. xiv, fig. 9. Miuliolina oblonga, Montagu, sp., H. B. Brady, 1884, Rep.
Chall., vol. ix, p. 160, pl. v, figs. 4a, b. Goés, 1894, Kongl. Svenska Vet.-Akad. Handl.,
vol. xxv, p. 110, pl. xx, figs. 850-850f. Chapman, 1907, Journ. Linn. Soc. Lond., Zool.,
vol. xxx, p. 17, pl. ui, fig. 26.
The type species, with a porcellanous shell, has been recorded from the sub-
Antarctic islands of New Zealand, from 50-85 fathoms. The present variety differs in
the finely arenaceous material of the test. It is quite a constant form, for no por-
cellanous shells of this species were found in these dredgings. The elongated outline
readily serves to distinguish this particular variety from Muiliolina agglutinans.
Occurrence.—Sample No. 10, 372 fathoms, very rare ; No. 13, 462 fathoms, common ;
No. 14, 472 fathoms, rare ; No. 15, 655 fathoms, frequent.
Miliolina tricarinata, d’Orbigny, sp. (for references see previous Reports on
Foraminifera of Elevated Deposits.)
A species occurring in polar seas, both north and south. It is interesting to note
the unusually small dimensions of the present specimens, one measuring only -346 mm.
in length, as compared with a tropical example recorded by Dr. Brady,* measuring
4-45; the average size being rather less than midway between these two extremes.
Occurrence.—Sample No. 3, 121 fathoms, frequent ; No. 8, 353 fathoms, very rare.
Sub-family— HavERININE
Genus—Planispirina, Seguenza, 1880
Planispirina sphera, d’Orbigny, sp. (Plate I, fig. 8)
Biloculina sphera, d’Orbigny, 1839, Foram. Amér. Mérid., p. 66, pl. viii, figs.
13-16. H.B. Brady, 1884, Rep. Chall., vol. ix, p. 141, pl. ui, figs. 4a, b. Planispirina
sphera, d’Orbigny, sp., Schlumberger, 1891, Mem. Soc. Zool. France, vol. iv, p. 577,
woodcuts 45, 46. Chapman, 1909, Sub-Antaractic Islands of New Zealand, vol. 1,
art. xv, p. 324.
This species occurs sparingly in southern waters. The aperture in our specimens
is normal and clearly defined ; the labyrinthic opening being confined to deep-water
examples.
Occurrence.—Sample No. 3, 121 fathoms, one specimen, very small; No. 4, 153
fathoms, one specimen, typical (figured).
* Rep. Chall., vol. ix, 1884, p. 166.
60 REPORT ON FORAMINIFERA AND OSTRACODA
Planispirina bucculenta, Brady (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, rare.
Sub-family— PENEROPLIDINE
Genus—Cornuspira, Schultze, 1854
Cornuspira involvens, Reuss, sp. (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, rare ; No. 4, 153 fathoms, very rare.
Cornuspira foliacea, Philippi, sp. (Plate I, fig. 9)
Orbis foliaceus, Philippi, 1844, Enum. Moll. Srcil., vol. ii, p. 147, pl. xxiv, fig. 26.
Cornuspira foliaceus, Philippi, sp., H. B. Brady, 1884, Rep. Chall., vol. ix, p. 199,
pl. xi, figs .5-9. Chapman, 1907, Journ. Linn. Soc. Lond. Zool., vol. xxx, p. 24, pl. iii,
fig. 48.
This species does not seem to be a typically southern form, but it occurs as a fossil
in the Australian tertiary strata. In the living state it is commonly found in the
North Atlantic.
Occurrence.
Sample No. 3, 121 fathoms, very rare ; No. 8, 353 fathoms, rare.
Family—ASTRORHIZIDA
Sub-family— AsTRORHIZINZ
Genus—Pelosina, H. B. Brady, 1879
Pelosina cylindrica, H. B. Brady (Plate II, fig. 10)
Pelosina cylindrica, H. B. Brady, 1884, Rep Chall., vol. ix, p. 236, pl. xxvi,
figs. 1-6.
This species varies considerably in shape and texture, according to the material
taken up in the construction of the test. It keeps, however, within the definition
given by Dr. Brady, and always contains a large proportion of mud in its cylindrical
tube. The foraminiferal shells built into the test are thin and small compared with
those selected by genera such as Rhizammina and Rhabdammina. <A few sponge
spicules are sometimes included in the mud walls, but not to so great an extent as in
Technitella. The examples found here vary from 28-5 mm. in length.
It is somewhat strange to meet with this species in such comparatively moderate
depths, for it has been recognised as a peculiarly deep-water form. The Challenger
records it from the Antarctic Ice Barrier at 1475 fathoms.
Occurrence.—Sample No. 3, 121 fathoms, rare; No. 5, 171 fathoms, very rare ;
No. 7, 225 fathoms, very rare ; No. 9, 360 fathoms, rare.
Pelosina rotundata, H. B. Brady (Plate II, fig. 11)
Pelosina rotundata, H. B. Brady, 1879, Quart. Journ. Micr. Sci., vol. xix, N.S.,
p- 31, pl. iii, figs. 4, 5. Idem, 1884, Rep. Chall., vol. ix, p. 236, pl. xxv, figs. 18-20.
Millett, 1899, Journ. Roy. Micr. Soc., p. 249, pl. iv, fig. 1.
This present specimen is subglobular, and suggests T'echnitella in the abundance
REPORT ON FORAMINIFERA AND OSTRACODA 61
of sponge spicules used in the construction of its test ; but they are mainly concentrated
at two points on the periphery, whilst the wall itself is composed of fine grey mud,
with an occasional spicule.
The above species is rare, being sparsely scattered over a wide area. It does not
appear to have been previously recorded from the Pacific.
Occurrence.—Sample No. 1, 110 fathoms, one specimen.
Sub-family—SaccaMMININ &
Genus—Saccammina, M. Sars, 1868
Saccammina spherica, M. Sars (Plate I, fig. 12)
Saccammina spherica, M. Sars, H. B. Brady, 1884, Rep. Chall., vol. ix, p. 253,
pl. xviii, figs. 11-17. Flint, 1899, Rep. U. S. Nat. Mus. for 1897, p. 269, pl. ix, fig. 2.
The tests of the Antarctic specimens are coarsely arenaceous, and are distinguished
from Psammosphera by the small, inconspicuous, papillate aperture.* Sometimes
two chambers are conjoined very firmly, after the manner of the Carboniferous species,
S. fusuliniformis, McCoy, sp. (usually erroneously referred to as S. cartert).t
S. spherica is found living within the Arctic Circle, and was only twice recorded by
the Challenger—once in deep water in the North Pacific, east of Japan, 2050 fathoms,
and at the Antarctic Ice Barrier.{ Ithas also been noted by Dr. Flint from the South
Atlantic, off the Coast of Brazil, at 1019 fathoms. It will thus be seen that, whereas
in the higher latitudes it is found in only moderately deep water, in low latitudes it is
invariably found at abyssal depths. Its path through the interpolar tracts, whether
in the Atlantic or Pacific, has been along the deepest parts of those ocean basins.
Occurrence.—Sample No. 3, 121 fathoms, common ; No. 4, 153 fathoms, frequent ;
No. 5, 171 fathoms, frequent.
Sub-family— RHABDAMMININ&
Genus—Hyperammina, H. B. Brady, 1878
Hyperammina elongata, H. B. Brady (Plate I, fig. 13)
Hyperammina elongata, H. B. Brady, 1884, Rep. Chall., VOloixs ps 25%, pl. xan,
figs. 4, 7-10.
H. elongata is chiefly a N. Atlantic form, and has occurred as far north as Franz-
Josef Land. It has been previously recorded from the Southern Ocean between the
Cape of Good Hope and Kerguelen Island at 1570 fathoms.
Occurrence.—Sample No. 7, 225 fathoms, very rare ; No. 9, 360 fathoms, very rare.
Genus—Marsipella, Norman, 1878
Marsipella elongata, Norman (Plate II, fig. 14)
Marsipella elongata, Norman, 1878, Ann. Mag. Nat. Hist., ser. 5, vol. i, p. 281,
pl. xvi, fig. 7. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 264, pl. xxiv, figs. 10-19.
Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 270, pl. xu, fig. 1.
* Since this description was written, Messrs. Heron-Allen and Earland have published an ex-
haustive examination of the grounds of separation of Psammosphera fusca and Saccammina
spherica, and have dissipated the suggestion that the two forms are identical (see Journ. R. Micr.
Soc. 1913, pp. 1-26, pl. 1-1v).
+ Chapman, Ann. Mag. Nat. Hist., ser. 7, vol. i, 1895, p. 215, woodcut.
t Brady, op. supra cit., p. 252.
Ir I
62 REPORT ON FORAMINIFERA AND OSTRACODA
It is of great interest to find this species in the Antarctic Sea, for it is otherwise
almost exclusively a North Atlantic form. M. elongata has been recorded by Dr.
Flint from the West Indian seas, and it has been met with once in the South Atlantic,
and occasionally in the South Pacific.
The present examples are typical; the proportion of fine arenaceous mud prepon-
derating, however, over the spicular material in the construction of the test.
Occurrence.—Sample No. 8, 353 fathoms, rare.
Marsipella cylindrica, H. B. Brady (Plate H, fig. 15)
Marsipella cylindrica, H. B. Brady, 1884, Rep. Chall., vol. ix, p. 265, pl. XXIV,
figs. 20-22.
The figured specimen of the present series is a regularly tapering and gently curved
variety ; whilst another example from the same sounding 1s enormously large compared
with those already known, measuring as much as 13 mm. in breadth at the widest end.
The species is a typically delicate and slender form in the Faroe Channel dredgings
at 530 and 542 fathoms. It has also been found in the South Atlantic and South
Pacific, generally at great depths.
Occurrence.—Sample No. 14, 472 fathoms, two specimens.
Family —LITUOLID
Sub-family —LirvoLinz
Genus—Reophax, Montfort, 1808
Reophax spiculifera, H. B. Brady (Plate III, fig. 16)
Reophax spiculifera, H. B. Brady, 1879, Quart. Journ. Mier. Sct., vol. sabe, INAS iss
p. 54, pl. iv, figs. 10,11. Idem, 1884, Rep. Chall., vol. ix, p. 295, pl. xxxi, figs. 16, 17.
The tests of the Antarctic specimens are short, consisting of few segments, but
they are otherwise typical. As an organism showing strong selective power in regard
to the material from which it constructs its tests, it is most remarkable. The ac-
companying arenaceous genera here comprise forms like Haplophragmiwn, and the
truly arenaceous species of Reophar, as R. dentaliniformis, together with arenaceous
Milioline, all of which employ siliceous sand grains for the walls of the test.*
This species has occurred at Sombrero Island, West Indies, 450 fathoms; Kerguelen
Island, 20-120 fathoms; near the Sandwich Islands, 2350 fathoms; off Kandavu,
255 and 610 fathoms; and off Tahiti, 620 fathoms.
Occurrence.—Sample No. 12, 460 fathoms, very rare; No. 14, 472 fathoms, rare ;
No. 15, 655 fathoms, rare.
* The following note, written by Sir John Murray on the same subject, occurs in the Challenger
Report, Summary of Results, pt. i, 1895, p. 511: ‘“‘ Among the arenaceous species from Sta. 157 there
are many interesting illustrations of the mode in which these Rhizopods select and arrange the
various particles in the deposit to form their tests. Astrorhiza crassatina here forms its test almost
exclusively of the spherical Radiolarian Cromyosphera Antarctica ; Storthosphera selects the finest
mineral particles, with an oceasional larger particle of quartz or palagonite ; one form selects only
the shells of the pelagic Foraminifera, and another only the smallest Diatomacez ; Reophax nodulosa
makes use of many large Coscinodisci, arranging them flat ways over the surface, and Rhabdammina
abyssorum forms its tube of the larger angular fragments of quartz, felspar, magnetite, and other
mineral particles.”
See also Heron-Allen and Farland (Journ. Quek. Micr. Club, ser. 2, vol. x, 1909, pp. 403-412,
pl. xxxii-xxxv) for an interesting account of the occurrence of a foraminifer, Technitella thompsont,
which constructs its test of the plates of Holothuria sp.
REPORT ON FORAMINIFERA AND OSTRACODA 63
Reophax dentaliniformis, H. B. Brady (Plate III, fig. 17)
Reophax dentaliniformis, H. B. Brady, 1881, Quart. Journ. Mier. Scv., vol. xxi,
N.S., p. 49. Idem, 1884, Rep. Chall., vol. ix, p. 293, pl. xxx, figs. 21, 22. Goés, 1894,
K. Svenska Vet.-Akad. Handl., vol. xxv, p. 25, pl. vi, figs. 172-175. Millett, 1899,
Journ. B. Mier. Soc., p. 254. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 274,
pl. xvii, fig. 2.
Tests varying in composition from fine to coarse material in the same sounding,
and consisting of angular quartz grains varied by occasional augite granites. The
shallowing of deep-water species as they advance to the polar seas is strikingly brought
to notice by such forms as the present, which typically mhabit great depths in inter-
tropical regions. Dr. Brady, in the Challenger Report, notes only four out of twenty-
one stations where it was found in less depths than 1000 fathoms. It is a widely
distributed, but generally rare, form.
Occurrence.—Sample No. 4, 153 fathoms, rare; No. 5, 171 fathoms, common ;
No. 7, 225 fathoms, frequent; No. 9, 360 fathoms, frequent; No. 13, 462 fathoms,
very rare; No. 14, 472 fathoms, rare; No. 15, 655 fathoms, rare.
Reophax longiscatiformis, sp. nov. (Plate IIT, fig. 18)
Description.—Test arenaceous, straight or very slightly curved, consisting of a
series of long, ovoid, somewhat irregular segments with deeply incised transverse
sutures. Length of test figured (fragmentary), 144 mm. ; greatest width, 173 mm.
This species is rare in the Antarctic soundings, being represented by two examples.
It is interesting as an isomorphous form, comparable with d’Orbigny’s hyaline species,
Nodosaria longiscata,* which is a well-known tertiary fossil.
Occurrence.—Sample No. 9, 360 fathoms ; No. 13, 462 fathoms.
Reophax murrayana, sp. nov. (Plate III, fig. 19)
Description.—Test finely arenaceous and spiculose; slender, gently curved and
gradually tapering to a blunt point; consisting of numerous segments slightly longer
than wide, with sutures nearly at right angles to length of shell. Length of test 1°88 mm. ;
greatest width, 115 mm.
This figured specimen, which cannot be matched with already known types of
Reophaz, is isomorphous with a Nodosaria (Dentalina) of the type of Nodosaria (Dentalina)
consobrina, d’Orbigny, var. emaciata, Reuss.¢ The sample of mud from which it was
taken was very small, otherwise more examples might have been found.
Named in honour of Mr. James Murray, F.R.S.E., of the British Antarctic Ex-
pedition of 1907-9, who superintended the zoological work of the expedition.
Occurrence.—Sample No. 7, 225 fathoms.
Genus—Haplophragmium, Reuss, 1860
Haplophragmium canariense, VOrbigny, sp. (Plate HI, fig. 20)
Nonionina canariensis, V@Orbigny, 1839, Foram. Canaries, p. 128, pl. u, figs:
33, 34. Haplophragmium canariense, dOrbigny, sp., H. B. Brady, 1884, Rep.
* Foram. Foss. Vienne, 1846, p. 32, pl. i, figs. 10-12. See also Sherborn and Chapman, Journ.
Roy. Micr. Soc., 1899, p. 486, pl. xi, figs. 17, 18. :
+ Dentalina emaciata, Reuss, Zeitschr. d. deutsch. geol. Gesellsch., vol. i, 1851, p. 63, pl. ii,
fig. 9.
64 REPORT ON FORAMINIFERA AND OSTRACODA
Chall., vol. ix, p. 310, pl. xxxv, figs. 1-5. Egger, 1893, Abhandl. k. bayer. Akad. Wiss.,
Cl. II, vol. xvin, p. 261, pl. v, figs. 27-29. Millett, 1899, Journ. Roy. Mier. Soc., p. 359.
Chapman, 1907, Journ. Quek. Micr. Club, p. 126, pl. ix, fig. 3. Idem, 1909, Sub-
Antarctic Islands of N. Zealand, vol. i, art. xv, p. 327, pl. xiv, fig. 6. Idem, 1901,
Journ. Iinn. Soc. Lond., Zool., vol. xxx, p. 400.
Tests small, with very neatly finished walls, generally of a warm brown colour,
and consisting of a moderately fine mosaic of sand grains.
A very widely distributed species, which has already occurred, amongst other places,
round New Zealand and the sub-Antarctic islands, as well as at Kerguelen and Heard
Islands.
Occurrence.—Sample No. 3, 121 fathoms, very common, some specimens excessively
minute ; No. 4, 153 fathoms, very common; No. 5, 171 fathoms, frequent ; No. 7,
225 fathoms, very rare ; No. 13, 462 fathoms, rare ; No. 14, 472 fathoms, very rare.
Haplophragmium latidorsatum, Bornemann, sp. (Plate III, fig. 21)
Nonionina latidorsata, Bornemann, 1855, Zeitschr. d. deutsch. Geol. Gesellsch., vol. vii,
p. 339, pl. xvi, figs. 4a,b. H. latidorsatum, Bornemann, sp., H. B. Brady, 1884, Rep.
Chall., vol. ix, p. 307, pl. xxxiv, figs. 7-10, 14. Goés, 1894, K. Svenska Vet.-Akad.
Handl., vol. xxv, p. 21, pl. v, figs. 102-120.
This cosmopolitan species is, generally speaking, a deep-water form ; but towards
the polar regions affects more moderate depths. A sample of a dredging from the
cold-water area of the Faroe Channel, sent me by my friend Mr. A. Earland, consists
largely of the tests of the above species.
Occurrence.—Sample No. 9, 360 fathoms, frequent ; No. 12, 460 fathoms, very rar ‘
No. 14, 472 fathoms, very rare.
Haplophragmium scitulum, H. B. Brady (Plate III, fig. 22)
Haplophragmium scitulum, H. B. Brady, 1881, Quart. Journ. Mier. Sci., vol. xxi,
N.S., p. 50. Idem, 1884, Rep. Chall., vol. ix, p. 308, pl. xxxiv, figs. 11-13. Flint,
1899, Rep. U.S. Nat. Mus. for 1897, p. 276, pl. xx, fig. 2.
The Challenger localities show this form to be widely distributed, although it is not
a common species, ranging over the Atlantic and Pacific Ocean beds from north to
south, the most southerly point being on the west coast of Patagonia at 400 fathoms.
Dr. Flint records it also from the west coast of Cuba.
Occurrence.—Sample No. 13, 462 fathoms.
Family—TEXTULARIIDA
Sub-family—TExTULARIINE
Genus—Valvulina, d’Orbigny, 1826
Valvulina fusca, Williamson, sp. (Plate III, figs. 23a, 6)
Rotalina fusca, Williamson, 1858, Rec. Foram. Gt. Brit., p. 55, pl. v, figs. 114, 115.
Valvulina fusca, Williamson, sp., H. B. Brady, 1884, Rep. Chall., vol. ix, p. 392,
pl. xlix, figs. 13, 14.
Dr. Brady records this species as a common North Atlantic foraminifera. It has also
occurred in the South Pacific, in the North Pacific, and in the West Indies.
Occurrence.—Sample No. 5, 171 fathoms.
REPORT ON FORAMINIFERA AND OSTRACODA 65
Sub-family—BuLm™ nin
Genus—Virgulina, d@’Orbigny, 1826
Virgulina schreibersiana, Czjzek, p. (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, rare.
Genus—Boliwvina, d’Orbigny, 1839
Bolivina textilarioides, Reuss (Plate III, fig. 24)
Bolivina textilarioides, Reuss, 1862, Srtzwngsb. d. k. Akad. Wiss. Wren, vol. xlvi,
p. 81, pl. x, fig. 1. H. B. Brady, 1884, Rep. Chall., vol. ix, p. 419, pl. lu, figs. 23-25 ;
Chapman, 1907, Journ. Linn. Soc. Lond., Zool., vol. xxx, p. 31, pl. iv, fig. 79.
This record appears to be new for the Southern Ocean. It is a fairly deep-water
form and appears to have been of commoner occurrence in Cretaceous and Tertiary
seas,
Occurrence.—Sample No. 3, 121 fathoms ; one specimen, small but typical.
Sub-family—CassIDULININ &
Genus—Cassidulina, d’Orbigny, 1826
Cassidulina oblonga, Reuss (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, very rare; No. 2, 113 fathoms, very
common ; No. 3, 121 fathoms, rare ; No. 4, 153 fathoms, common ; No. 5, 171 fathoms,
very common.
Cassidulina parkeriana, H. B. Brady (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, very rare ; No. 2, 113 fathoms, common ;
No. 3, 121 fathoms, frequent ; No. 4, 153 fathoms, common; No. 5, 171 fathoms,
common.
Casstdulina subglobosa, H. B. Brady (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, frequent ; No. 2, 113 fathoms; No. 3,
121 fathoms, small specimens, frequent ; No. 4, 153 fathoms, common; No. 5, 171
fathoms, small, frequent ; No. 7, 225 fathoms, very rare; No. 8, 353 fathoms, very
rare.
Genus—Ehrenbergina, Reuss, 1849
Ehrenbergina serrata, Reuss (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, rare ; No. 4, 153 fathoms, very common ;
No. 5, 171 fathoms, very rare.
66 REPORT ON FORAMINIFERA AND OSTRACODA
Family—LAGENIDA
Sub-family—LaGEnIna&
Genus—Lagena, Walker and Boys, 1784
Lagena globosa, Montagu, sp. (Plate IV, fig. 25)
Vermiculum globosum, Montagu, 1803, Test. Brit., p. 523. Lagena globosa, Montagu,
sp., Reuss, 1863, Setzwngsb. d. k. Akad. Wiss. Wien, vol. xlvi, p. 318, pl. i, figs. 1-3.
Kgger, 1899, Abhandl. k. bayer. Akad. Wiss., Cl. UL, vol. xxi, p. 102, pl. v, fig. 3;
Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv, p. 333.
A cosmopolitan species, not affected to any great extent by depth or latitude.
Occurrence.—Sample No. 3, 121 fathoms, rare ; No. 8, 353 fathoms, very rare.
Lagena apiculata, Reuss, sp. (Plate IV, fig. 26)
Oolina apiculata, Reuss, 1851, Haidinger’s Naturw. Abhandl., vol. iv, Abth. i,
p. 22, pl. 1, fig. 1. Lagena apiculata, Reuss, 1863, Sitzwngsb. d. k. Akad. Wiss. Wien,
vol. xlvi, p. 318, pl. i, figs. 1, 4-8, 10, 11. H. B. Brady, 1884, vol. ix, p. 453, pl. lvi,
figs. 4, 15-18. Chapman, 1900, Quart. Journ. Geol. Soc., vol. lvi, p. 258, pl. xv, fig. 3.
A widely distributed species.
Occurrence.—Sample No. 3, 121 fathoms, one specimen.
Lagena schlichti, A. Silvestri, sp. (Plate IV, fig. 27)
Lagena marginata, Walker and Boys, var., Millett, 1901, Journ. Roy. Micr. Soc.,
p- 497, pl. viii, fig. 20. Fissurina schlichti, A. Silvestri, 1902, Mem. d. Pont. Acc. Rom.
d. Nuovi Lincei, vol. xix, p. 14; woodcuts, figs. 9-11. Lagena schlichti, A. Silvestri, sp.,
Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv, p. 337, pl. xv,
figs. 7a, b.
This species appears to be widely distributed, and was formerly confused with
L. marginata, Walker and Boys. It has already occurred in soundings from the sub-
Antarctic islands of New Zealand, at depths of 50-85 fathoms.
Occurrence.—Sample No. 3, 121 fathoms, common ; No. 4, 153 fathoms, frequent ;
No. 5, 171 fathoms, very rare.
Lagena marginata, Walker and Boys (Plate IV, fig. 28)
Serpula (Lagena) marginata, Walker and Boys, 1784, Test. Min., p. 2, pl. i, fig. 7.
Lagena marginata, Walker and Boys, H. B. Brady, 1884, Rep. Chall., vol. ix, p. 476, pl. lix,
fig. 22. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv, p. 335,
pl. xv, fig. 6.
This species has a wide range, and is found in both polar seas. It has already been
recorded from near the Antarctic Ice Barrier, and from the sub-Antarctic islands of New
Zealand. The figured specimen closely approaches the form L. levigata, Reuss.
Occurrence.—Sample No. 3, 121 fathoms, rare ; No. 4, 153 fathoms, very rare.
Lagena orbignyana, Seguenza, sp. (Plate IV, fig. 29)
Fissurina orbignyana, Seguenza, 1862, Foram. Monotal. Miocen. Messina, p. 6,
pl. ui, figs. 65, 66. Lagena orbignyana, Seguenza, sp., Flint, 1899, Rep. U.S. Nat.
REPORT ON FORAMINIFERA AND OSTRACODA 67
Mus. for 1897, p. 308, pl. liv, fig. 4. Chapman, 1909, Sub-Antarctic Islands of New
Zealand, vol. i, art. xv, p. 337, pl. xv, fig. 10.
This widely distributed species has been recorded off the Falkland Islands at 6
fathoms. It was also found at 60-85 fathoms around the sub-Antarctic islands of New
Zealand.
Occurrence.—Sample No. 3, 121 fathoms, one specimen ; No. 4, 153 fathoms, one
specimen.
Sub-family—Noposarin®
Genus—Nodosaria, Lamarck, 1816
Sub-genus—Glandulina, d’Orbigny, 1826
Nodosaria (Glandulina) levigata, d’Orbigny (for references see previous Reports
on Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, very common ; No. 4, 153 fathoms, rare.
Nodosaria (Glandulina) rotundata, Reuss (for references see previous Reports
on Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, one specimen ; No. 3, 121 fathoms, very
common ; No. 4, 153 fathoms, frequent.
Sub-genus—Dentalina, d’Orbigny, 1826
Nodosaria (Dentalina) communis, d’Orbigny (Plate IV, fig. 30)
Nodosaria (Dentalina) communis, d’Orbigny, 1826, Ann. Scz. Nat., vol. vii, p. 254,
No. 35. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 310, pl. lvi, fig. 2. Chapman,
1909, Sub-Antarctic Islands of New Zealand, vol. i, art. xv, p. 341, pl. xv, fig. 10.
This common species is another of those usually found in moderately shallow water
in high latitudes.
Occurrence.—Sample No. 4, 153 fathoms.
Genus—Cristellaria, Lamarck, 1818
Cristellaria crepidula, Fichtel and Moll, sp. (for references see previous Reports
on Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, one specimen ; No. 4, 153 fathoms, one
specimen.
Cristellaria articulata, Reuss (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 4, 153 fathoms, one specimen.
Sub-family— PoLYMORPHININ/
Genus—Polymorphina, d’Orbigny, 1826
Polymorphina oblonga, d’Orbigny (Plate IV, fig. 31)
Polymorphina oblonga, d’Orbigny, 1846, Foram. Foss. Vienne, p. 232, pl. xii, figs.
29-31. Hgger, 1893, Abhandl. d. k. bayer. Akad. Wiss., Cl. II, vol. xviii, p. 309,
pl. x1, figs. 9, 10, 24.
68 REPORT ON FORAMINIFERA AND OSTRACODA
As regards the distribution of this species, the records for the southern hemisphere
include Table Bay, Mauritius, and West Australia. It was found by the Challenger at
Tongatabu at 240 fathoms; and at Raine’s Islet, Torres Strait, at 155 fathoms. P.
oblonga is not uncommon in shore sands near Melbourne (Port Phillip) ; and typical
fossil examples are found in the Balcombian deposits (Oligocene) of Victoria.
Occurrence.—Sample No. 5, 171 fathoms, one specimen.
Genus— Uvigerina, d’Orbigny, 1826
Uvigerina pygmea, d’Orbigny (Plate IV, fig. 32)
Uvigerina “pygmea, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii, p. 269, pl. xii, figs.
8, 9; modéle No. 67. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 320, pl. Ixviii,
fig. 2. Chapman, 1905, Journ. N. Zealand Inst., vol. xxxviii, p. 99.
The range of this generally well-known species is stated by Dr. H. B. Brady * to
extend to about lat. 46° S. in the Southern Ocean; and to 79° N. at Smith’s Sound
and the shores of Franz-Josef Land. It has lately been obtained by the author from
soundings off Great Barrier Island, New Zealand at 110 fathoms.
Occurrence.—Sample No. 8, 353 fathoms, one specimen.
Uvigerina angulosa, Williamson (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, rare; No. 2, 113 fathoms, common ;
No. 3, 121 fathoms, very common; No. 4, 153 fathoms, very common; No. 5, 171
fathoms, frequent.
Family—GLoBIGERINIDZ
Genus—Globigerina, d’Orbigny, 1826
Globigerina bulloides, d’Orbigny (Plate IV, fig. 33)
Globigerina bulloides, d’Orbigny, 1826, Ann. Sci. Nat., vol. vii, p. 277, No. 1,
modéles Nos. 17 and 76. Rhumbler, 1900, in K. Brandt’s Nordisches Plankton, Heft
14, p. 21, figs. 24-26. Wright, 1900, Geol. Mag., N.S., Dec. 4, vol. vii, p. 100, pl. v,
fig. 18. Chapman, 1909, Swb-Antarctic Islands of New Zealand, vol. i, art. xv, p. 350.
The present examples are thin-shelled, but otherwise typical. It is somewhat
common in the Southern Ocean; a few of the Challenger stations being Kerguelen
Island, Heard Island, and south-west of Patagonia. It is also of frequent occurrence
amongst the sub-Antarctic islands of New Zealand.
Occurrence.—Sample No. 3, 121 fathoms, frequent ; No. 8, 353 fathoms, rare.
Globigerina triloba, Reuss (Plate IV, fig. 34)
Globigerina triloba, Reuss, 1849, Denkschr. d. k. Akad. Wiss. Wien, vol. i, p. 374,
pl. xlvii, fig. 11. Chapman, 1909, Sub-Antarctic Islands of New Zealand, vol. i, art.
XV, p. 350. ;
A characteristic specimen, having a thicker test than the examples of the preceding
species. Previously recorded from the Southern Ocean.
Occurrence.—Sample No. 10, 372 fathoms, one specimen.
* Challenger Rep., vol. ix, p. 575.
REPORT ON FORAMINIFERA AND OSTRACODA 69
Globigerina inflata, d’Orbigny (Plate V, fig. 35)
Globigerina inflata, d’Orbigny, 1839, Foram. Cuba, p. 134, pl. i, figs. 7-9. Rhumbler,
1900, in K. Brandt’s Nordisches Plankton, Heft 14, p. 19, fig. 19.
The above form is here characteristic and abundant ; but it occurs only in one
sample. According to Dr. H. B. Brady it is not so common a form in the Arctic and
Southern Oceans as in areas of lower latitudes. and that author also notes its southern
limit at lat. 53° 55” S.
Occurrence.—Sample No. 8, 353 fathoms, very common.
Globigerina dutertrei, d’Orbigny (Plate V, fig. 36)
Globigerina dutertret, d’Orbigny, 1839, Foram. Cuba, p. 95, pl. iv, figs. 19-21. H. B.
Brady, 1884, Rep. Chall., vol. ix, p. 601, pl. Ixxxi, figs. la-c.
This species is recorded by Dr. H. B. Brady asa starved representative of G. bulloides,
in the Antarctic Seas. It has been already recorded from the Antarctic Ice Barrier,
both in the surface water and the bottom ooze. It is here very rare, as it was also
in the sub-Antarctic island dredgings off New Zealand.
Occurrence.—Sample No. 3, 121 fathoms, one specimen ; No. 4, 153 fathoms, one
specimen.
Globigerina equilateralis, H. B. Brady (Plate V, fig. 37)
Globigerina cequilateralis, H. B. Brady, 1879, Quart. Journ. Mier. Scv., vol. xix,
N.S., p. 71. Idem, 1884, Rep. Chall., vol. ix, p. 605, pl. Ixxx, figs. 18-21. Rhumbler,
1900, in K. Brandt’s Nordisches Plankton, Heft 14, p. 20, figs. 21-23.
A fine typical example. Previously recorded by the Challenger as far south as the
Cape of Good Hope. This species also occurred around the sub-Antarctic islands of
New Zealand, and the present record pushes it still farther southward.
Occurrence.—Sample No. 8, 353 fathoms,
Genus—Pullenia, Parker and Jones, 1862
Pullenia quinqueloba, Reuss (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, frequent ; No. 4, 153 fathoms, common.
Family—ROTALITDA
Sub-family— Roraiin &
Genus—Truncatulina, d’Orbigny, 1826
Truncatulina refulgens, Montfort, sp. (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 1, 110 fathoms, one specimen; No. 2, 113 fathoms,
frequent ; No. 3, 121 fathoms, common ; No. 4, 153 fathoms, very common ; No. 5,
171 fathoms, one specimen.
Truncatulina lobatula, Walker and Jacob, sp. (for references see previous
Reports on Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 2, 113 fathoms, one specimen; No. 3, 121 fathoms,
frequent. No. 4, 153 fathoms, frequent ; No. 5, 171 fathoms, frequent.
It K
70 REPORT ON FORAMINIFERA AND OSTRACODA
Truncatulina tenera, H. B. Brady (Plate V, fig. 38)
Truncatulina tenera, H. B. Brady, 1884, Rep. Chall., vol. ix, p. 665, pl. xev,
figs. lla-c. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 334, pl. Ixxvu, fig. 4.
It is extremely interesting to meet with this rare form, which was found by Dr.
Brady in soundings at the Canaries, North Atlantic, 620 fathoms ; and at three stations
near the coast of Chili and Patagonia at 166 to 1375 fathoms. Dr. Flint has since
discovered it off the west coast of Patagonia at 194 fathoms.
Occurrence.—Sample No. 8, 353 fathoms.
Genus—Anomalina, d’Orbigny, 1826
Anomalina ammonoides, Reuss, sp. (Plate V, fig. 39)
Rosalina ammonoides, Reuss, 1845, Verst bohm. Kreid. pt. i, p. 36, pl. xin, fig.
66; pl. viii., fig. 53. Anomalina ammonoides, Reuss, sp., H. B. Brady, 1884, Rep.
Chall., vol. ix, p. 672, pl. xciv, figs. 2, 3. Flint, 1899, Rep. U.S. Nat. Mus. for 1897,
p. 335, pl. Ixxvii, fig. 4.
The farthest southerly record of this form appears to be that of Dr. Brady, from the
west coast of New Zealand at 275 fathoms.
Occurrence.—Sample No. 3, 121 fathoms, one specimen ; No. 8, 353 fathoms, one
specimen.
Anomalina polymorpha, Costa (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 8, 353 fathoms, rare.
Pulvinulina elegans, var. partschiana, d’Orbigny, var. (Plate V, fig. 40)
Rotalina partschiana, VOrbigny, 1846, Foram. Foss. Vienne, p. 153, pl. vii, figs.
28-30; pl. viii, figs. 1-3; Pulvinulina partschiana, d’Orbigny, sp., H. B. Brady,
1884, Rep. Chall., vol. ix, p. 699, pl. cv, figs. 3a-c, woodcut 21. Millett, 1904, Journ.
Roy. Mier. Soc., p. 502.
The present occurrence is apparently new for this part of the Southern Ocean ; the
Challenger having previously noted it off the Cape of Good Hope (Sta. 142).
Occurrence.—Sample No. 8, 353 fathoms, rare.
Family—NUMMULINIDAL
Sub-family— PoLysToMELLIN &
Genus—Nonionina, d’Orbigny, 1826
Nonionina depressula, Walker and Jacob, sp. (Plate V, fig. 41)
Nautilus depressulus, Walker and Jacob, 1798, Adams’ Essays, Kanmacher’s ed.,
p. 641, pl. xiv, fig. 33. Nonionina depressula, Walker and Jacob, sp., Wright, 1900, Geol.
Mag. Dec. 4, vol. vii, p. 100, pl. v, fig. 23.
This widely distributed species is found in the Arctic Seas. It has been recorded
by Dr. Haeusler from the Hauraki Gulf, New Zealand, and by the writer from the
sub-Antarctic islands of New Zealand.
Occurrence.—Sample No. 3, 121 fathoms, frequent ; No. 4, 153 fathoms, common.
REPORT ON FORAMINIFERA AND OSTRACODA 71
Nonionina stelligera, d Orbigny (for references see previous Reports on
Foraminifera of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms, rare.
Nonionina scapha, Fichtel and Moll, sp., var. bradi, var. nov. (Plate V, fig. 42)
Nonionina (?) scapha, Fichtel and Moll, sp., H. B. Brady, 1884, Rep. Chall.,
vol. ix, p. 730, pl. cix, fig. 16.
The specific form, N. scapha, has been recorded from, amongst other places, the
Hauraki Gulf, New Zealand (Haeusler), and round the sub-Antarctic islands of New
Zealand (Chapman).
The present variety was figured by Dr. Brady as a doubtful form of N. scapha ;
and our example exactly resembles it in having an evolute commencement. One of
the specimens figured by Dr. Flint,* in his group of NV. scapha is also comparable to the
above variety.
Occurrence.—Sample No. 3, 121 fathoms, one specimen.
Genus—Polystomella, Lamarck, 1822
Polystomella crispa, Linné, sp. (Plate V, fig. 43)
Nautilus crispus, Linné, 1767, Syst. Nat., 12th ed., p. 1162-275. Polystomella
crispa, Linné, sp., Egger, 1893, Abhandl. k. bayer. Akad. Wiss., Cl. I, vol. xvii, p. 432,
pl. xx, figs. 20, 21. Flint, 1899, Rep. U.S. Nat. Mus. for 1897, p. 338, pl. lxxx, fig. 3.
This ubiquitous species has already been recorded as far south as the sub-Antarctic
islands of New Zealand and Kerguelen Island.
Occurrence.—Sample No. 8, 353 fathoms, rare ; shells complanate and thin.
DESCRIPTION OF THE OSTRACODA
Section—PODOCOPA
Family—Cyprip&
Genus—Aglaia, G. 8. Brady, 1867
(2?) Aglaia obtusata, G. 8. Brady (Plate VI, fig. 44)
(2) Aglaia obtusata, G. 8S. Brady, 1880, Rep. Chall., Zool., pt. ii, p. 35, pl. xxx,
figs. 8a-d. Chapman, 1910, Journ. Linn. Soc. Lond., Zool., vol. xxx, p. 426.
This rare species has been found in only three localities, the earlier occurrences
being Kerguelen Island, 20-50 fathoms (Brady) ; and Funafuti, 1050 fathoms (Chap-
man).
Occurrence.—Sample No. 3, 121 fathoms, one specimen (carapace).
Genus—Pontocypris, G. O. Sars, 1865
Pontocypris (2) faba, Reuss, sp. (Plate VI, figs. 45a, 6)
Bairdia faba, Reuss, 1855, Zeitschr. d. deutsch. Geol. Gesellsch., p. 278, pl. x, fig. 2.
Pontocypris faba, G. 8. Brady, 1878, Trans. Zool. Soc., p. 382, pl. lxin, figs. 6a-e.
Pontocypris (2) faba, Reuss, sp., idem, 1880, Rep. Chall., Zool., pt. ili, p. 37, pl. 1,
* Rep. U.S. Nat. Mus. for 1897 (1899), pl. Ixxx, fig. 1.
72 REPORT ON FORAMINIFERA AND OSTRACODA
figs. 4a-d. Pontocypris faba, Reuss, sp., Egger, 1901, Abhandl. k. bayer. Akad. Wiss., vol.
xxi, Abth. ii, p. 420, pl. iv, figs. 44, 45. Pontocypris (2) faba, Reuss, sp., Chapman,
1910, Journ. Linn. Soc. Lond., Zool., vol. xxx, p. 427.
Should the specific correlation of this form with Reuss’s be correct, the species dates
from Cretaceous times. It also occurs in the Pliocene (Antwerp Crag) of Europe. At
the present day it is entirely restricted to the waters of the southern hemisphere,
being recorded from Bass Strait and Honolulu in shallow water, from Funafuti at the
great depth of 1050 fathoms, and from Mauritius in moderately deep water.
Occurrence.—Sample No. 1, 110 fathoms, one specimen (carapace) of an amber-
brown colour, with the animal preserved within.
Family—CyTHERID&
Genus—Cythere, Muller, 1785
Cythere foveolata, G. 8. Brady (for references see previous Reports on
Ostracoda of Elevated Deposits)
Occurrence.—Sample No. 4, 153 fathoms, one diminutive valve.
Cythere davisi, sp. nov. (Plate VI, figs. 46a-c)
Description.—Shell of the female, seen from the side, oblong, subrectangular, with
rounded extremities ; highest at the anterior hinge-joint, height more than half the
length ; anterior border obliquely rounded at the dorsal angle, strongly curved towards
the ventral, with the anterior edge set with numerous short, sharp spines ; posterior
border rounded, and armed with some moderately long sharp spines ; dorsal line slightly
concave in the centre, and elevated towards the anterior border ; ventral edge nearly
straight, but for a broad depression coinciding with an excavated area on the median
surface under the subcentral tubercle ; surface tumid in the median area, and covered
with fine, polygonal areole, each with a central papilla; the subcentral boss also
areolated and pitted ; submarginal flange well developed on the extremities and ventral
border ;a sharp salient ridge runs obliquely towards the posterior half of the sub-
marginal flange, abruptly turning at right angles near the posterior margin, and finally
thinning away at the post-dorsal angle ; a conspicuous tubercle with fossa over the
anterior hinge-joit. Kdge view, from below, elongate subcordate, increasing in width
from front to back up to the middle of the posterior third of the carapace ; with rounded
outline below, irregular above, interrupted by the median depression. End view
short, subcordate, almost triangular, but with rounded faces. Carapace of the male
more elongate and compressed.
Measurements.—Length of figured example, 1-423 mm. ; greatest height, -73 mm. ;
thickness of carapace, -7 mm.
The above species was at first tentatively regarded as a variety of C. wyville-
thomsoni, G. 8. Brady,* to which it is related in general form. It differs essentially,
however, in having a much thicker carapace, in its rounded posterior extremity, in
having a median depression, and in the feeble polygonal surface ornamentation.
This species is named in honour of Capt. J. K. Davis, of the 8.Y. Nimrod, who
collected the present samples of soundings in the Antarctic.
Occurrence.—Sample No. 3, 121 fathoms, frequent ; No. 7, 225 fathoms, one speci-
men. All the examples are complete carapaces.
* Rep. Chall., Zool., pt. iii, 1880, p. 82, pl. xx, figs. 4a-f.
REPORT ON FORAMINIFERA AND OSTRACODA 73
Cythere quadriaculeata, G. 8. Brady (Plate VI, fig. 47)
Cythere quadriaculeata, G. 8. Brady, 1880, Rep. Chall., Zool., pt. iii, p. 86, pl. xxii,
figs. 2a-d ; pl. xxv, figs. 4a-d ; Chapman, 1910, Journ. Linn. Soc. Lond., Zool., vol. xxx,
. 432.
Dr. Brady gives two Challenger stations for this species, viz. the Inland Sea, Japan
(15 fathoms), and off the reefs at Honolulu (40 fathoms). The Funafuti specimens
occurred at the great depths of 1050 and 1215 fathoms.
Occurrence.—Sample No. 4, 153 fathoms, one valve of moderately strong build.
Cythere normani, G. 8. Brady (for references see previous Reports on
Ostracoda of Elevated Deposits)
Occurrence.—Sample No. 4, 153 fathoms, frequent ; all single valves.
Genus—Xestoleberis, G. O. Sars, 1865
Xestoleberis variegata, G. S. Brady (Plate VI, fig. 48)
Xestoleberis variegata, G. S. Brady, 1880, Rep. Chaill., Zool., pt. iii, p. 129, pl. xxx1,
figs. 8a-g ; Chapman, 1910, Journ. Linn. Soc. Lond., Zool., vol. xxx, p. 435.
This species was found in both deep and shallow water round Funafuti ; and it
often occurred in the atoll’s lagoon. Dr. Brady’s records for the species are Cape
Verde, Tongatabu, Fiji, and Noumea.
Occurrence.—Sample No. 4, 153 fathoms, one valve ; No. 8, 353 fathoms, one valve.
Xestoleberis davidiana, Chapman (for description see previous Reports on
Ostracoda of Elevated Deposits)
Occurrence.—Sample No. 3, 121 fathoms ; one carapace ; No. 4, 153 fathoms, one
valve.
Xestoleberis setigera, G. S. Brady (Plate VI, fig. 49)
Xestoleberis setigera, G. S. Brady, 1880, Rep. Chall., Zool., pt. il, p. 125, pl. xxxi,
figs. 2a-d ; figs. 3a-c ; Egger, 1901, Abhandl. k. bayer. Akad. Wiss., vol. xxi, Abth. 01,
p. 456, pl. iii, figs. 37-39.
This species appears to be almost restricted to the Southern Ocean. Brady records
it from Kerguelen Island, 120 fathoms; Heard Island, 75 fathoms; and Prince
Edward’s Island, 50-150 fathoms. Egger’s specimens came from the coast of Liberia,
West Africa.
Occurrence.—Sample No. 3, 121 fathoms, one carapace ; No. 4, 153 fathoms, rare ;
No. 5, 171 fathoms, one valve.
Genus—Cytherura, G. O. Sars, 1865
Cytherura obliqua, G. 8. Brady (Plate VI, fig. 50)
Cytherura obliqua, G. 8. Brady, 1880, Rep. Chall., Zool., pt. ii, p. 181, pl. xxxil,
figs. la-d.
The only other locality for this species is that which furnished Dr. Brady with his
described specimens, viz., Balfour Bay, Kerguelen Island, 20-50 fathoms. The
single valve found in the present series is prominent on the ventral face, but otherwise
typical.
Occurrence.—Sample No. 4, 153 fathoms, one valve.
74 REPORT ON FORAMINIFERA AND OSTRACODA
Cytherura rudis, G. 8S. Brady (Plate VI, fig. 51)
Cytherura rudis, G. 8. Brady, 1868, Ann. Mag. Nat. Hist., ser. 4, vol. 11, p. 34, pl. v,
figs.15-17; Cytherura (%) rudis, G. 8. Brady, 1880, Rep. Chall., Zool., pt. iii, p. 132,
pl. xxxii, figs. 3a-d. Cytherura rudis, G.S. Brady and Norman, 1889, Trans. Roy. Dubl.
Soc., ser. ii, vol. iv, p. 204, pl. xviii, figs. 10-12; pl. xix, fig. 21.
The present occurrence of the above species is most interesting from the point of
view that it helps to dispel Dr. Brady’s doubt regarding the identity of the
Challenger specimens from the Straits of Magellan (55 fathoms) with the original
examples obtained by Brady many years earlier from Davis’s Straits. The present
Antarctic specimen is nearer the Arctic form in outline ; and the rough polygonal
sculpturing is intermediate in character between the southern and northern examples
recorded by Dr. Brady. The additional localities for this species given by Drs. Brady
and Norman are—Godhavn Harbour, Greenland, 5-25 fathoms ; Ginevra Bay, Spitz-
bergen ; Smith’s Sound, 210 fathoms. Also as a pleistocene fossil at Portland, Co.
Maine, U.S.A., and in Scotland, at Loch Gilp.
Occurrence.—Sample No. 7, 225 fathoms, one valve.
SUMMARY OF RESULTS
In the foregoing Report, 64 species and varieties of Foraminifera and 11 species
of Ostracoda are described or recorded. Among the Foraminifera the following are
new :
Miliolina subrotunda, Mont. sp., var. striata ;
A oblonga, Mont. sp., var. arenacea ;
Reophaz longiscatiformis ;
i murrayana; and
Nonionina scapha, F. and M. sp., var. bradii.
There is also a new species of the Ostracoda, viz. Cythere davisi.
A notable feature in the present foraminiferal fauna is the large number of species
which are undoubtedly common to the cold areas of the north and south polar regions.
Amongst these may be cited: Saccammina spherica, Haplophragmium canariense,
H. latidorsatum, Virgulina schreibersiana, Lagena apiculata, L. marginata, Polymorphina
oblonga, Uvigerina pygmea, Globigerina bulloides, G. inflata, Truncatulina lobatula,
Nonionina depressula, N. stelligera, and Polystomella crispa.
The Ostracoda here recorded are almost peculiarly a southern oceanic fauna; a
marked exception is Cytherura rudis, already known from Spitzbergen, Greenland, and
other localities in the Far North. One or two species, however, have a somewhat ex-
tensive range, as will be seen on referring to the distributional notes with each species.
Of the bipolar species of Foraminifera, Saccammina spherica is perhaps the most inter-
esting, since it has been almost exclusively obtained from stations in high latitudes, and
only twice in low latitudes, in the North Pacific and South Atlantic, both in deep water.
In this, as in other species of bipolar Foraminifera, the following fact is clearly brought
out: that these tiny organisms, born and bred in the richer, shallow mud-zones of
high latitudes, sink into deeper water areas when spreading out through the tropical
and inter-tropical seas, and again graduate into shallower marine conditions as they
approach the polar regions. The shallow-water foraminiferal fauna of warmer latitudes,
on the other hand, show, broadly speaking, a restricted field. _In the two recorded
occurrences of Saccammina spherica in inter-tropical seas, it will be noticed that the
stations are both situated in main axes of abyssal troughs trending north and south.
The existence of a selective instinct implanted in the Foraminifera is here given
further proof in the case of Reophax spiculifera ; for, although living side by side with
R. dentaliniformis, a form whose test is an agglutination of comparatively coarse,
angular sand grains, it rejects this material in favour of short, siliceous sponge spicules,
with which awkward material it constructs fairly neat, long, funnel-shaped chambers,
resembling in shape the straw covers of wine bottles.
In the following Table of Bathymetrical Distribution, it will be seen how remarkable
a feature is the segregation of many species of Foraminifera within a bathymetrical
zone or series of depths within certain limits. This peculiarity of the fauna may, of
course, be largely induced by the nature of the sea bottom in supplying suitable food
and building material.
75
76 REPORT ON FORAMINIFERA AND OSTRACODA
LIST OF FORAMINIFERA AND OSTRACODA FROM THE ANTARCTIC SOUNDINGS
(S.Y. NIMROD)
BATHYMETRICAL DIsTRIBUTION IN FaTHOMS
SPECIES
110} 113 | 121 | 153 | 171 | 225 | 353 | 360 | 372 | 460 | 462 | 472 | 655 | Page
FoRMINIFERA
Biloculina depressa, d’ Orb. : x
ee elongata, d’Orb 5 De | Oz || Oz© ||
bradii, Schl... ai | Pee
e rregularis, @Orb. . xX
Spiroloculina canaliculata, d’ Orb.
Miliolina subrotunda, Mont. sp.,
var. striata, var. nov.
vulgaris, d’Orb. sp.
bicornis, W. & J. sp. .
agglutinans, d’ Orb. sp.
oblonga, Mont. sp., var.
arenacea, var. nov.
5 tricarinata, d’ Orb. sp.
Planispirina sphera, @ Orb. sp.
5 bucculenta, Brady
Cornuspira involvens, Rss. sp. .
a foliacea, Phil. sp.
Pelosina cylindrica, Brady
E rotundata, Brady
Saccammina spherica, Sars
Hyperammina elongata, Brady .
Marsipella elongata, Norman
a cylindrica, Brady
Reophax spiculifera, Brady
» dentaliniformis, Brady
» longiscatiformis, sp. nov.
» murrayana, sp. nov.
Haplophragmium canariense,
d’Orb. sp. .
latidorsatum,
Born. sp.
A. scitulum,
Brady
Valvulina fusca, Will. sp.
Virgulina schreibersiana, Cz. sp.
Bolivina textilarioides, Rss.
Cassidulina oblonga, Rss.
Ay parkeriana, Brady .
+ subglobosa, Brady .
Ehrenbergina serrata, Rss.
Lagena globosa, Mont. sp.
apiculata, Rss. sp.
schlichti, Silv.
marginata, W. & B.
» orbignyana, Seg. sp.
Nodosaria (G.) levigata, d’ Orb.
= (G.) rotundata, Rss. .
5 (D.) communis, d’Orb.
ww
www
bd bd bd bd bd bd
bd
WKH
HK KKH KKM hh KK
Hh nA WA
REPORT ON FORAMINIFERA AND OSTRACODA 77
LIST OF FORAMINIFERA AND OSTRACODA FROM THE ANTARCTIC SOUNDINGS (continued)
BATHYMETRICAL DISTRIBUTION IN FATHOMS
SPECIES
110} 113 | 121 | 153 | 171 | 225 | 353 | 360 | 372 | 460 | 462 | 472 | 655
FORAMINIFERA—cont.
Cristellaria crepidula, F. & M. sp. x
Pe articulata, Rss.
Polymorphina oblonga, @Orb. . xX
Uvigerina pygmea, @ Orb.
Pe angulosa, Will. [econ | eX
Globigerina bulloides, VOrb. . x
a triloba, Rss. . a x
55 inflata, d’Orb.
ri dutertrei, a’ Orb. DG |) Dk
Pa equilateralis, Brady
Pullenia quinqueloba, Rss. ; xX | xX
Truncatulina eee Mont.
we
va
ve
b4
4
Ps Pees Ww. & i
sp. dG || 2z¢ |) 2€ || 2:8
aS tenera, "Brady
Anomalina ammonoides, Rss. sp. x
= polymorpha, Costa .
Pulvinulina elegans, var. parts-
chiana, d’Orb. var.
Nonionina depressula, W. & J.
sp. 5
an stelligera, d’Orb.
95 scapha, F. & M. sp.,
var. bradw, var. n.
Polystomella crispa, L. sp. : xX
vale
va
bd
a
OsTRACODA
(2) Aglaza obtusata, G.S.B. : x
Pontocypris (?) faba, Rss. sp. . | X
Cythere foveolata, G.S.B. :
» davisi, sp.nov. . x
* quadriaculeata, G.S.B.
» normani, G.S.B.
Xestoleberis variegata, GSB.
3 davidiana, Chapm.
ys setigera, G.S.B.
Cytherura obliqua, G.S.B. ‘
ie rudis,G.S.B. . ; ».4
vale
WK MK Hh
a
EXPLANATION OF THE PLATES
PLATE I
Figure 1.—Biloculina bradii, Schlumberger. Sample No. 1, 110 fathoms. x 13.
FicurE 2.—Spiroloculina canaliculata, d’Orbigny. Sample No. 8, 353 fathoms. x 26.
Figure 3.—Miliolina subrotunda, Montagu, sp., var. striata, var. nov. Sample No. 8,
353 fathoms. x 52.
Figure 4.—M. vulgaris, d’Orbigny, sp. Sample No. 8, 353 fathoms. x 26.
Figure 5.—M. bicornis, Walker and Jacob, sp. Sample No. 8, 353 fathoms. x 52.
Figure 6.—M. agglutinans, d’Orbigny, sp. Sample No. 9, 360 fathoms. x 52.
Figure 7.—M. oblonga, Montagu, sp., var. arenacea, var. nov. Sample No. 13, 462
fathoms. x 52.
FicurE 8.—Planispirina sphera, d’Orbigny, sp. Sample No. 4, 153 fathoms. x 26.
Figure 9.—Cornuspira foliacea, Philippi, sp. Sample No. 3, 121 fathoms. x 26.
PLATE II
Figure 10.—Pelosina cylindrica, Brady. Sample No. 3, 121 fathoms. x 10.
Ficure 11.—P. rotundata, Brady. Sample No, 1, 110 fathoms. x 10.
FiGuRE 12.—Saccammina spherica, M. Sars. Sample No. 3, 121 fathoms. x 20.
Figure 13.—Hyperammina elongata, Brady. Sample No. 9, 360 fathoms. x 35.
FiguRE 14.—Marsipella elongata, Norman. Sample No. 8, 353 fathoms. x 26.
FicurE 15.—M. cylindrica, Brady. Sample No. 14, 472 fathoms. x 20.
PLATE III
FiIcuRE 16.—Reophax spiculifera, Brady. Sample No. 15, 655 fathoms. x 26.
FicuRE 17.—R. dentaliniformis, Brady. Sample No. 9, 360 fathoms. x 26.
FicurE 18.—R. longiscatiformis, sp. nov. Sample No. 9, 360 fathoms. x 26.
FicuRE 19.—R. murrayana, sp. nov. Sample No. 7, 225 fathoms. x 26.
FicureE 20.—Haplophragmium canariense, d’Orbigny, sp. Sample No. 3, 121 fathoms.
x 26.
78
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
FIGURE
REPORT ON FORAMINIFERA AND OSTRACODA 79
21.—H. latidorsatum, Bornemann, sp. Sample No. 14, 472 fathoms. x 26.
22.—H. scitulum, Brady. Sample No. 13, 462 fathoms. x 26.
23.—Valvulina fusca, Williamson, sp.: a, side view ; }, oral aspect. Sample
No. 5, 171 fathoms. x 26.
24.—Bolivina textilarioides, Reuss. Sample No. 3, 121 fathoms. x 56.
PLATE IV
25.—Lagena globosa. Montagu, sp. Sample No. 8, 353 fathoms. x 52.
26.—L. apiculata, Reuss, sp. Sample No. 3, 121 fathoms. x 52.
27.—L. schlichti, A. Silvestri. Sample No. 3, 121 fathoms. x 52.
28.—L. marginata, Walker and Boys. Sample No. 3, 121 fathoms. x 52.
29.—L. orbignyana, Seguenza, sp. Sample No. 4, 153 fathoms. x 52.
30.—Nodosaria (Dentalina) communis, d’Orbigny. Sample No.4, 153 fathoms.
x 52.
31.—Polymorphina oblonga, d’Orbigny. Sample No. 5, 171 fathoms. x 26.
32.—Uvigerina pygmea, d’Orbigny. Sample No. 8, 353 fathoms. x 26.
33.—Globerigina bulloides, d’Orbigny. Sample No. 3, 121 fathoms. x 52.
34.—G. triloba, Reuss. Sample No. 10, 372 fathoms. x 52.
PLATE V
35.—Globigerina inflata, A’ Orbigny. Sample No. 8, 353 fathoms. x 52.
36.—G. dutertrei, d’Orbigny. Sample No. 3, 121 fathoms. x 52.
37.—G. equilateralis, Brady. Sample No. 8, 353 fathoms. x 52.
38.—Truncatulina tenera, Brady. Sample No. 8, 353 fathoms. x 52.
39.—Anomalina ammonoides, Reuss, sp. Sample No. 3, 121 fathoms. x 52.
40.—Pulvinulina elegans, var. partschiana, d’Orbigny, var. Sample No. 8, 353
fathoms. x 52.
41.—Nonionina depressula, Walker and Jacob, sp. Sample No. 3, 121 fathoms.
x 52.
42.—N. scapha, Fichtel and Moll., sp., var. bradii, var.nov. Sample No. 3, 121
fathoms. x 52.
43.—Polystomella crispa, Linné, sp. Sample No. 8, 353 fathoms. x 52.
80
FIGURE
FIGURE
FIGURE
FIGURE
Figure
FIGURE
FIGURE
FIGURE
REPORT ON FORAMINIFERA AND OSTRACODA
PLATE VI
44,—(?) Aglaia obtusata, G. S. Brady. Right valve. Sample No. 3, 121
fathoms. x 40.
45.—Pontocypris (?) faba, Reuss, sp.: a, right valve; b, ventral aspect.
Sample No. 1,110 fathoms. x 26.
46.—C. davisi, sp. nov.: a, left valve; 6, ventral edge view; ¢, posterior
end view. Sample No. 3, 121 fathoms. x 26.
47.—COythere quadriaculeata, G. 8. Brady. Left valve. Sample No. 4, 153
fathoms. x 52.
48.—Xestoleberis variegata, G. 8. Brady. Left valve. Sample No. 4, 153
fathoms. x 52.
49.—X. setigera,G. 8S. Brady. Left valve. Sample No. 3, 121 fathoms. x 26.
50.—Cytherura obliqua, G. 8. Brady. Left valve. Sample No. 4, 153 fathoms.
x 42.
51.—C. rudis, G.S. Brady. Left valve. Sample No. 7, 225 fathoms. x 52.
PLATE I
Fic. 4
Fic. 8
lic. 6.
Fic. 9
F.C. ad nat. del.
ANTARCTIC FORAMINIFERA.—-S.Y. NIMROD, 1909
[To face p. 80
PLATE II
F.C. ad nat. del
ANTARCTIC FORAMINIFERA.—S.Y. NIMROD, 1909
PLATE III
F.C. ad nat. del.
ANTARCTIC FORAMINIFERA.—-S.Y. NIMROD, 1909
PLATE IV
F.C. ad nat. del.
ANTARCTIC FORAMINIFERA.—S.Y. NIMROD, 1909
PLATE V
F.C. ad nat. del.
ANTARCTIC FORAMINIFERA.—S.Y. NIMROD, 1909
PLATE VI
Fic. 48
lic. 50
F.C. ad nat. del.
“ANTARCTIC OSTRACODA.—S.Y. NIMROD, 1909
PART IV
REPORT ON A PROBABLE CALCAREOUS
ALGA
FROM THE CAMBRIAN LIMESTONE BRECCIA FOUND IN
ANTARCTICA AT 85° S.
(With Plate)
BY
FREDERICK CHAPMAN, A.L.S., F.R.MLS.
Palzontologist to the National Museum, Melbourne
INTRODUCTORY
SEVERAL distinct types of fossil remains in Cambrian limestone from various parts
of the world have been referred, and probably rightly so, to the calcareous alge.
Notably amongst these are Confervites primordialis of Bornemann* (from Sardinia),
also recorded by Von Toll} (from Siberia) ; Epiphyton flabellatum, Bornemann{ (from
Sardinia) ; and Siphonema [ =Girvanella] incrustans § and (?) arenaceum, Bornemann ||
(from Sardinia).
The genus Confervites above mentioned has generally been made a dumping-ground
for all organisms resembling modern seaweeds having a simple or branching thread-
like thallus. It seems tolerably certain that many of these simple seaweed-like
forms, to whatever botanical group they may belong, existed in prodigious abundance
in the earliest known rocks ; the evidence being strengthened by the fact that a large
number of these forms cannot be referred to trails, stains, or cracks in the sediments,
nor do they come within the definition of any group of animal organisms. Regarding
Confervites, Seward § remarks : “‘ Numerous fossils have been referred to this genus
by different authors, but they are for the most part valueless and need not be further
considered.” That author subsequently says (p. 178): “It is possible that this
[Confervites Chantransioides of Bornemann] is a fragment of a Cambrian alga, but the
figures and description do not afford by any means convincing evidence.”
The present specimens form a considerable proportion of the limestone. They
* “Die Versteinerungen des cambrischen Schichtensystems der Insel Sardinien,” Kats. Leop.-
Carol Deutsche Akad. Naturforscher, vol. li, 1887, p. 16, pl. ii, figs. 5, 6.
+ ‘ Beitriige zur Kenntniss des sibirischen Cambrium, Pt. I,” Mem. Acad. Imp. Sci. St. Petersb.,
Ser. VIII, vol. viii, No. 10, 1899, p. 47, pl. viii, figs. le, d, text fig. 9.
{ Bornemann, loc. supra cit., p. 16, pl. i, figs. 9, 10.
§ Idem, loc. cit., p. 18, pl. ii, figs. 1, 2. See also Chapman, Rep. Aust. Assoc. Adv. Sci. Adelaide
Meeting, 1907, p. 7 (sep. copy), foot-note j, where it is stated that Bornemann’s species is synony-
mous with Girvanella problematica, Nich. and Eth. fil.
|| Idem, loc. cit., p. 19, pl. ii, fig. 3.
§| Fossil Plants, vol. i, Cambridge, 1898, p. 177.
II 81 M
82 REPORT ON A PROBABLE CALCAREOUS ALGA
show a marked feature of growth as a living organism, since they appear normally
attached to shell fragments and what seem to be the remains of crinoid ossicles.
They possess a distinct wall to each thread-like cell, and the character of the wall is
such that it could not possibly have resulted from infiltration. These tubular and
tulty organisms occur in a series of slides cut from the pebble of a limestone breccia
containing Archeocyathine, and are closely related to the before-mentioned Epiphyton
flabellatum, Born. These specimens also bear some resemblance to Von Toll’s figure
of Confervites primordialis (loc. supra cit:), but there: the (?) thallus is not distinctly
spreading in radial fashion, the tubular structure being more or less parallel ;
in which feature it further differs from Bornemann’s type figure. Von Toll’s text
figure of the Siberian organisms also shows a series of transverse connecting-rods
which bind the thallus together, but which are absent in Bornemann’s specimens, and
are exhibited to a slight degree in the present examples.*
A very close resemblance exists ‘between the present form and Bornemann’s
generic type, Hpiphyton. In the species figured by that author (H. flabellatum) the
thallus is fan-shaped and irregularly, alternately grouped to form comparatively large
spreading masses. In the Antarctic species—which specimens, by the way, are all of
smaller dimensions—the thallus is less complex, nearly always consisting of isolated
tufts. It has a habit of nestling within or growing upon calcareous organisms
similar to that of Bornemann’s species.
The only other organism with which the genus Epiphyton could be reasonably
compared is Solenopora ; which has of late years been shown to have a strong claim
to relationship with the calcareous alge.t In fact, at first sight, 1t seemed nearest
allied to that genus. In some features the two. genera show certain resemblances, as
in the fascicular grouping of thread-like cells and their division by sparsely distributed
horizontal partitions ; but the parallel or elongately radial character of the former
affords a distinctive feature between the two kinds of organisms. Solenopora,
moreover, never shows, so far as known, the short radial, fascicular habit of Epuphyton.
DESCRIPTION OF THE SPECIES
Genus—Epiphyton, Bornemann, 1887 (? Confervites, Von Toll, 1899)
Epiphyton fasciculatum, sp. n. (Plate I, Figs. 1-8)
Thallus fasciculate and fan-shaped; consisting of radial and branching tubes ;
often occurring in isolated tufts, but normally growing in alternate clusters of two
or many more.{ Tubes irregularly cylindrical, constricted at intervals and interrupted
by more or less horizontal partitions, disposed in fan-shaped groups’; the constrictions
impart a digitate character to the thallus. Extremities of the tubes sometimes
widening and bluntly truncated. Thallus often flat or subconvex at the base, owing
to its habit of attaching itself to hollow surfaces ; rounded or dome-shaped on the
distal surface. A transverse section of the thallus shows it to be thick and radial in
structure. Cells in cross-section massed, closely adpressed, subrounded to polygonal.
* Tt is probable that Von Toll’s so-called Confervites primordialis is really referable to Epiphyton,
and not to Confervites, considering the habit of growth shown in his pl. viii, figs. e and d, and his
description that it grows in tufty masses on the Archaocyathine of the Cambrian limestone of
Torgoschino.
+ “On the Structure and Affinities of the Genus Solenopora,” Geol. Mag., Dec. 4, 1894, p. 145.
{ The habit of growth makes it appear a microscopic facsimile of the Cambrian Oldhamia
antiqua, Forbes.
FROM THE CAMBRIAN LIMESTONE BRECCIA 83
Cell-walls of clear granular calcite ; mterior infilled with a dark grey granular material.
Where massed together the individual cell-walls can always be singled out by a dark
line separating each tube.
Measurements.—Average height of thallus, single tufts, about 5mm. Aggregated
tufts about 4 mm., or even more, in diameter. Average width of cells, ‘05 mm.
Observations.—The Sardinian species, EL. flabellatum, shows the same general habit
of growth as the Antarctic form, but the organism is of stronger and larger growth,
the tubular cells are stouter, and the plan of dichotomy is different; since E. fasci-
culatum 1s characterised by the forked terminals of the cells being more slender and
more regularly cylindrical than in E. flabellatum, whilst their extremities, seen in
section, present a tuning-fork shape by the forked tips tending to become parallel.
The dimensions of £. flabellatum are in every way greater than in E. fasciculatum,
as the following table will show:
Diameter of tubes . . . 4H. fasciculatum . . . 0°05 mm.
E. flabellatum . . . 0°08 mm.
Average length of tufts. . FE. fasciculatum . . . OO} mm.
HE. jflabelatum* >. - .' OF mm.
Occurrence.—In a pebble of Cambrian limestone breccia, containing Archeo-
cyathinoids, oolite grains, and ostracods. Obtained by Wild on the Southern
journey, 85° S. An important organism, constituting a large proportion of the lme-
stone.
Notes on the more important occurrences in the slides —No. 2.—A good, typically
thin section, showing some fine examples of Epiphyton, which exhibit the general
characters (Paratype). No. 69.—Globular masses of the organisms, drifted into a
recess. No. 111.—Good rounded masses, not so digitate as usual. No. 114.—Small
flocculent masses of the organism. No. 115.—Finest example of EF. fasciculatum,
showing good detail (Type). No. 119.—Capitate specimen. No. 122.—Pellet-like
masses, seen in a rather thick section.
EXPLANATION OF THE PLATE
FicurE 1.—Epiphyton fasciculatum, sp. nov. Showing the fine ramified (7?) thallus
attached to a quadrate fragment, probably a crinoid ossicle. Paratype. Slide
No. 2. X 28.
Ficure 2.—E£. fasciculatum, sp. noy. A group of the organism, showing well-preserved
walls. Cut mainly in a transverse or oblique direction to the tubes. Type.
Slide No. 115. x 28.
Ficure 3.—E. fasciculatum, sp. nov. The same more highly magnified, showing the
double structure of the cell-walls. Slide No. 115. x 180.
84
PLATE I
Brean BIG. 3
I’.C, photomicr.
EPIPHYTON FASCICULATUM, sp. Nov. IN CAMBRIAN LIMESTONE FROM
I
ANTARCTICA AT 85° S.
[To face p. 84
PART V
REPORT ON MOLLUSCA
FROM ELEVATED MARINE BEDS, “RAISED BEACHES,”
OF McMURDO SOUND
(With Three Figures in the Tecat)
BY
CHARLES HEDLEY, F.L.S.*
From the mud of the “ Raised Beach” Mr. R. E. Priestley carefully collected a large
series of shells, mostly of small size. These specimens are so fresh and glossy that
they appear to have come direct from the sea, rather than to be fossils. Probably
the low temperature has assisted to save them from that decay which in a mild climate
and a similar situation might have overtaken them. Still, it seems safe to assume
that their geological age is of the slightest, and that all will ultimately be found to
still exist in McMurdo Sound.
Comparing this collection with the shells dredged by the expedition, on which I
have already reported, a difference is noticeable in the presence, absence, and relative
abundance of various shells. The explanation may be that the “raised beach” was
upheaved from a deeper horizon than the dredgings represent. Mr. Murray} has
explained that shell beaches are not permitted by the ice to accumulate in the
Antarctic. It follows that the deposit under examination is not a “ beach” in the
ordinary acceptance of the term.
Only the Belgica Expedition has hitherto collected Scissurella euglypta, Pelseneer,t
which is therefore a gain to this hemisphere.
In the following list of these subfossil shells a star (*) indicates that it was recorded
among the recent shells of the Expedition.
GASTEROPODA
Scissurella euglypta, Pelseneer.
*Valvatella refulgens, Smith.
a crebrilirulata, Smith.
minutissima, Smith.
* This paper was written in October 1910 and proofs sent to the writer in January 1916.
During five years’ editorial custody, the conchological nomenclature has been extensively revised,
so that to bring the article up to date it would be necessary to restudy the subject and rewrite the
article. Only ordinary press corrections have been made.—C. H.
+ Murray, ante, vol. i, “ Biology,” 1909, p. 2.
{ Pelseneer, Moll. “ Belgica’? Exped., 1908, p. 17, ff, 48-45.
II 85 N
86 REPORT ON MOLLUSCA
Lacuna macmurdensio, Hedley.
*Rissoa adarensis, Smith.
* fraudulenta, Smith.
id glacialis, Smith.
deserta, Smith.
- gelida, Smith.
sp.
*Capulus subcompressus, Pelseneer.
*Lovenella austrina, Hedley.
* antarctica, Smith.
*Vermicularia murrayi, Hedley.
Turbonilla polaris, Hedley.
Eulima convexa, Smith.
*Thesbia innocens, Smith.
*Trophon longstaffi, Smith.
Trophon priestleyi, Hedley.
*Odostomiopsis major, Hedley.
Retusa frigida, Hedley.
LAMELLIBRANCHIATA
* Adacnarca nitens, Pelseneer.
*Philobrya limoides, Smith.
*Pecten colbecki, Smith.
*Lima hodgsoni, Smith.
*Thracia meridionalis, Smith.
*Cardita astartoides, Martens.
*Kellya nimrodiana, Hedley.
Tellimya antarctica, Smith.
The novelties are described as follows :
Turbonilla polaris, sp. nov. (Fig. 1)
Shell long and slender, constricted between the whorls. Adult whorls eight, well
rounded. Protoconch glassy, not immersed, of one and a half whorls at right angles
to the adult shell, its length slightly exceeding the breadth of the subsequent whorl.
Sculpture: smooth, vertical, round-backed ribs, parted by smooth and rounded
furrows of equal breadth ; on the last whorl these amount to twenty. A strong basal
keel receives and ends these vertical ribs ; its upper edge is visible above the suture
on the spire. Base smooth. Aperture rhomboid, columella straight. Length, 3°75 ;
breadth, 1 mm.
A single specimen, slightly fractured at the aperture, which may not be adult.
The genus had not previously been traced so far south.
REPORT ON MOLLUSCA 87
Trophon priestleyi, sp. nov. (Fig. 2)
Shell small, very solid, narrowly fusiform. Whorls five, including a smooth
pointed protoconch of a whorl and a half, suture marked by a narrow groove.
Sculpture: there are two prominent keels on the periphery, another much smaller
just above the sutural groove, and another small one on the shoulder; these reach
the outer edge of the lip. On the base of the last whorl are three more spirals, succes-
eS
Fic. 1 Fic. 2
sively diminishing anteriorly. These keels have thin, pinched, rather wavy edges,
and are separated by shallow furrows twice or thrice their breadth. Both keels and
interspaces are overridden by fine radiating threads. Aperture ovate, outer lip
bevelled within, inner lip slightly excavated. Canal short, broad, and slightly
recurved. Length, 5°5; breadth, 2°8 mm.
One entire specimen and a few fragments. It is unusual in Trophon for the radial
sculpture to be subordinate to the spiral. Such forms as T. petterdi, Crosse, and
T. plebius, Hutton, form a passage to the present form. I presume that Sipho antarc-
tidis, Pelseneer,* is related to the species now introduced.
* Pelseneer, Moll. ‘‘ Belgica” Exped. 1903, p. 22, f. 60.
88 REPORT ON MOLLUSCA
Retusa frigida, sp. nov. (Fig. 3)
Shell small, oval, slightly contracted at the waist, rounded below, gradate above.
Whorls three, the earlier prominent, with a half-turned-over tip. Suture deeply
furrowed. Surface glossy, smooth, except some almost imperceptible spiral grooves
on the shoulder. Aperture large, pyriform more than two-thirds the total length of
the shell, rounded in front, narrowly arched posteriorly. Outer lip advanced and
sinuate medially, inner hp shghtly curled over the long and deep umbilical furrow.
Length, 2°25; breadth, 1°25 mm.
One whole and another broken specimen. The novelty is nearest to R. antarctica,
Pfeffer,* from South Georgia, from which the axial furrow of the present species
clearly distinguishes it.
* Jahrb. wiss. Anst. Hamburg, III, 1886, p. 189, pl. 3, f. 5.
PAR “V1
REPORT ON ANTARCTIC SOILS
1334
H. I. JENSEN, D.Sc.
THEsE Antarctic soils, forwarded by Dr. Douglas Mawson, were submitted to me in
my official capacity as Assistant to the Chemical Branch of the Department of Agri-
culture, New South Wales, by my chief, Mr. F. B. Guthrie, F.C.S. Dr. Mawson supplied
the following introductory note in explanation :
INTRODUCTORY NOTE
“These four samples of ‘ soils’ were the nearest approach to true soil afforded by
the region of South Victoria Land visited by us. The first three samples were collected
by myself, the last one by Mr. R. E. Priestley.
“Numbers | and2 were got from the bottom of a slight depression, some seventy feet
above sea-level, a quarter of a mile north-east of the Hut at Cape Royds. At that
spot, before reaching the coarse gravels and kenyte lava below, there is about a foot
of what might be called soil. The actual surface was mantled with a thin layer of
very uniform gravel of particles about one-eighth of an inch in diameter. The gravel
is the residue left after the wind has carried off the finer stuff. It appears that after
the gravel has accumulated to a depth of about a quarter of an inch the fine material
below is protected from further deflation. Samples 1 and 2 were from the same spot,
the former representing layers several inches below the latter.
‘Sample 3 came from a moraine mound two hundred yards nearer Blue Lake.
“Sample 4 was collected by Priestley on the mainland of South Victoria Land,
in Dry Valley, on the western side of McMurdo Sound.
‘In no case was there anything in the nature of subsoil in the general acceptation
of the term.
‘‘Karth is quite a rare occurrence in South Victoria Land, for almost everywhere
that ice is absent, rock alone is met. Generally speaking, the earthy matter is only
rock-flour from ice abrasion ; thus mechanical disintegration is the rule. At the same
time there appears to be some chemical decay. It would appear that when depositions
of rock-flour have been exposed for long, that an appreciable amount of chemical
decomposition is effected.
“Referring to the water-soluble constituents of these soils, however, it is to be
remembered that the coastal regions are likely to be impregnated with sea salts in the
manner detailed in other sections of this volume.
‘«Some wheat was sown in a potful of a mixture of Nos. 1 and 2 of the described
samples.* In this experiment the wheat germinated earlier than usual and showed
unusual vigour and growth, demonstrating the suitability of the soil as a plant food.
“More than usual interest attaches to the examination of these soils, coming as they
do from a land where practically no vegetation exists.”
GENERAL ANALYSIS
These “ soils” proved of great interest, and the results of the analyses are given in
the Tables A and B.
* Experiment conducted at Adelaide.
II oO
90 REPORT ON ANTARCTIC SOILS
GENERAL NATURE OF THE SAMPLES
NumsBer 1. Black soil; mechanically a light loam. Largely derived from kenyte
lava, the prevailing rock of the neighbourhood. From a position six inches below the
surface at Cape Royds, Ross Island, Antarctica.
NumBer 2. Dark soil; mechanically a very sandy loam. Largely derived from
kenyte lava, the prevailing rock of the neighbourhood, but with some admixture of
ice-carried morainic mud. Taken between the surface and a depth of three inches, but
not including the half-inch of surface gravel ; Cape Royds.
The water-soluble constituents form little acicular crystals in the soil, and are probably
combined in the form of chlorides of sodium, potassium, and magnesium; sulphates
of magnesium, calcium, and potash; and carbonate of soda.
Numeer 3. Black soil; mechanically a very sandy, gravelly loam. Partly derived
from kenyte lava and partly from morainic matter. From between one and four inches
below the surface, on the top of a moraine mound, Cape Royds.
NumBer4. Light-coloured irregular and indefinite soil. Moraine silt derived largely
from Gneisses and Schists. From Dry Valley, South Victoria Land.
TABLE A. MECHANICAL ANALYSES OF ANTARCTIC SOILS
Absolute
Water weight Capillary power Root
Capacity Ibs. per acre | (inchesin 4 hours)! Fibres
6 in. deep
Number
Uh lbs. inches
25 (low) 1,866,853 over 9 (excel-
lent)
25 (low) 1,798,965 over 9 (excel-
lent)
28 (low) 2,040,000 over 9 (excel-
lent)
35 (fair) n.d. 5 (good) Sample insufficient
COMMENTS
In the table on p. 92 I have compared the above with
(a) a soil derived from alkaline lavas at Mittagong, N.S.W. ;
(b) a soil derived from basalt, Tweed Heads, Queensland; and
(c) a granite soil from the south coast (Moruya, N.S.W.).
From this table (p. 92) it appears that in spite of the abundant moisture from
melting snows the leaching out of mineral plant food does not take place with
anything like the rapidity of this process in moist soils of less frigid climate.
Rock weathering in Antarctica is much more a process of mechanical disintegration
than of chemical change into a normal soil. Zeolitic minerals form by slow hydration ;
carbonates also form very slowly, but the solution and removal of these acid soluble
minerals are much slower processes than their formation. So these minerals
accumulate in the sand grains without being leached away and thus breaking up the
grains into finer particles.
* Impalpable matter, chiefly clay.
91
REPORT ON ANTARCTIC SOILS
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92 REPORT ON ANTARCTIC SOILS
No. 1 No. 2 No. 3 | No. 4 A B C
(Cape | (Cape (Cape | (Dry Valley lAlkaline lava Go _ Granite
Royds) | Royds) Royds) | Antarctica) | (Mittagong) Heads) KSousnioss
Reaction : . | Strongly Strongly | Strongly Strongly Alkaline Very Acid
_ alkaline | alkaline | alkaline | alkaline strongly
acid
Water capacity .| 25% 259% 28% 35%, 50% 64% BBIOZ
(low) (low) (low) (fair) | (high) (low)
Capillary power . | Over 9” | Over 9” | Over 9” DE -- 52" 6"
(excellent) (excellent)(exeellent) (good) | (good) (good)
Clay . 5 . | 86:79 | 21-89% 8-5% | 43-0% 85% 24-2%,
Moisture ; . | 2:18% | 328% | 868% | 129% | 175% | 840% | 1:82%
Volume : . | 2:09% BOE 3:50% 1620/7 ie 8:7095) |) WS:99°Ca a 230,
N. ; : . | -028% | -028% | -028% | -028% | -151% | -392% | -126%
(def.) (def.) | (def.) (def.) (good) (good) | (satisfy.)
Ca0w CtiwtSt«iS*TCiB% | 1-0883% | 1:50% | 1-907% | -178% | -162% | -178%
(excellent) (excellent) (excellent) (excellent) (satisfy.) | (satisfy.) | (satisfy.)
KeOn : . | 8:298% | 2-703% | 38-22% | -765% | -108% | -029% | -047%
(excellent) (excellent) (excellent) (excellent) (satisfy.)| (bad) | (indif.)
P.O; 554%, | 894% | -65% | -328% | -058% | -102% | -049%
(vy. good) (good) |(vy. good) (good) (fair) (satisfy.) | (indif.)
|
Rock weathering under normal conditions consists, first, of the mechanical
disintegration of the rock into gravel and sand; next, the formation of veins of
secondary minerals in veins within these grains ; and, lastly, the solution of the secondary
minerals in organic acids causing further disintegration.
Only the first two of these processes are of importance in Antarctic weathering.
Consequently the accumulation of zeolites makes the soils appear chemically rich.
The cause of the absence of the third process lies in the absence of organic acids.
Organic matter in these soils is remarkably low. This is due to dearth of plant life,
the cause of which I propose to touch upon.
First, carbon dioxide is much lower in the air of frigid climates than in our climate.
Secondly, the cold regions of the earth have no thunderstorms, hence the precipitation
is not nitrified with nitric acid as in regions where thunderstorms are frequent. The
discharges of the aurora are probably not intense enough to make nitrogen combine
with oxygen. The want of the acids CO, and HNO, partly accounts for the small amount
of leaching. The want of nitric acid, together with the coldness of the climate, account
for the want of plant life, and hence of organic acids which would dissolve carbonates
and zeolites. Nitrifying bacteria, which can produce nitric acid and ammonia from
the air, cannot live in the cold, and plants do not thrive in the absence of nitrates.
The Antarctic soils are alkaline, which fact is due to the accumulation of salts,
carbonates, and zeolites, and the absence of organic acids.
In two of the soils (1 and 2) crystals of Glauber’s salt (mirabilite) existed in the
dried soil. The soil water is probably charged with this salt, which may probably
be derived from the decomposition of nosean in the alkaline lavas. Common salt
is also abundantly present, and is in the soils examined partly derived from marine
spray, but may partly be formed by the decomposition of sodalite.
The small percentage of nitrogen obtained in each estimation probably exists in the
form of ammonia salt from wind-blown penguin guano, or droppings from skua gulls.
PART VII
REPORT ON THE
PETROLOGY OF THE ALKALINE ROCKS OF
MOUNT EREBUS, ANTARCTICA
(With Five Plates)
BY
H. I. JENSEN, D.Sc.
THrouGH the kindness and courtesy of Professor David, F.R.S., C.M.G., Sir Ernest
Shackleton, and Mr. R. E. Priestley, F.G.8., of the South Pole Expedition of 1907-9,
I have been able to examine and classify the alkaline eruptive rocks of Mount Erebus
and Ross Island. In this work I have been greatly assisted by Mr. R. E. Priestley.
He cut sections and made a preliminary examination of a much larger number of
specimens of these rocks than I had time to devote attention to, and all the most
important types which he discovered he transferred to me for further investigation and
classification.
The eruptive rocks of Ross Island have microscopically, with very few exceptions,
strongly alkaline affinities. The exceptions consist entirely of olivine basalt, which,
though not an alkaline rock and commonly associated with calcic magmas, may yet
be a differentiation product of an alkaline magma. The olivine basalts do, I understand,
burst through the kenytes and other alkaline types, and are, where found, the final
products of volcanic activity. The other basic rocks, poor in alkali, such as limburgite
and magnetite basalt, are nevertheless types which are so commonly associated with
alkaline magmas and so rarely with calcic magmas that they are generally looked upon
as normal differentiation products of the former.
All the rocks dealt with in this part may be regarded as differentiates of a magma
of the composition of intermediate kenytes. The origin of the kenyte itself is a more
difficult problem.
In my paper on “ The Distribution, Origin . . . of Alkaline Rocks,” * I infer from
the sequence of Australian alkaline lavas that ‘“‘ basic lavas may rise along fractures
and intrude themselves into the alkaline zone”’ of the earth’s crust (for the supposed
existence of which several reasons were put forward in the same paper). “ Here they
will assimilate alkali, and also help to bring about a refusion of the whole alkaline
zone.” In this paper therefore the origin of basic alkaline rocks is ascribed to stoping,
assimilation, and solution of alkaline sedimentary and metamorphic rocks by a basaltic
magma from the zone of basic igneous rock, which is supposed to underlie the whole
of the earth’s crust.
Reginald A. Daly, in a paper on “ The Origin of Augite-Andesite . . .” + published
* Proc. Linn. Soc. of N.S.W., vol. xxxiii, pt. ii, 1908.
+ Jour. of Geol., July-August 1908.
I 93 P
94 PETROLOGY OF THE ALKALINE ROCKS
simultaneously with mine, ascribes most igneous magmas to assimilation of crustal
rocks by an olivine basalt magma. According to these views olivine basalt is the
primary magma. Through assimilation of alkaline sedimentaries of the earth’s crust
the kenyte mother magma has been formed. This, again, may produce olivine basalt
by differentiation.
In a more recent paper, entitled “‘ The Origin of Alkaline Rocks,” * Professor Daly
supposes these rocks to be differentiates from a normal basalt magma following inter-
action with limestones at a depth. This hypothesis seems a very probable one in
theory, chemically, physically, and mineralogically sound, but unfortunately the field
evidence in Australia lends it so far only little support. Yet I think it highly probable
that many alkaline and subalkaline bodies have originated in this way, and others in
the way I have suggested.
G. T. Prior has assigned the term “‘ Atlantic type” to all rocks which might under
the Rosenbusch classification be considered differentiates of a foyaitic magma. For
reasons given in my paper on ‘‘ The Distribution, Origin . . . of Alkaline Rocks,” I
prefer to call the type to which they belong “ Katepeiric.”
The lavas of Ross Island are in this report treated under the following headings :
. Trachyte.
. Acid Kenyte.
. Intermediate to Basic Kenytes.
. Trachydolerites (porphyritic basalts with alkaline affinities).
. Leucitophyres, Tephrites, and Basanites.
. Basalts without Olivine.
. Olivine Basalts.
. Limburgites. Magma Basalts.
. Magnetic Basalts.
Generally speaking, this order of treatment is one of decreasing acidity and
alkalinity, but a strictly natural arrangement is impossible, for the following reasons :
(a) The trachydolerite group passes insensibly into that of the lmburgites and
vice versa.
(b) Some of the tephrite-basanite group are more basic than the basalts with or
without olivine.
(c) The lhmburgites have stronger affinities with the trachydolerites and basanites
than with the basalts.
(d) The magnetite basalts sometimes have affinities with the kenytes.
The following schematic representation gives some idea of the relationships of these
rocks as far as petrological investigation can decide (vide p. 95).
CaS HPWH
1. THE TRACHYTES
Localities.—Most of the trachytes which were collected came from a parasitic cone
to which the name of Mount Cis has been given. Other trachytes were collected at
Observation Hill, Hut Point, Mount Bird, Turk’s Head, and a tuff cone on Ross Island.
In miscellaneous collections of erratics from Cape Royds and other parts several
trachytes were also contained.
(a) Mount Cis Trachytes.—Those from Mount Cis were the most typical trachytic
rocks collected. They belong to the group of phonolitic trachytes. The dominant
variety is a dark grey or greenish-black vesicular rock with a glistening sheen,
at once suggesting the presence of an abundance of sanidine or anorthoclase. The
* Bull. Geol. Soc. of America, vol. xxi, May 1910.
OF MOUNT EREBUS, ANTARCTICA
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96 PETROLOGY OF THE ALKALINE ROCKS
vesicles are empty steam cavities devoid of drusy infillings. The less vesicular
varieties are dark greyish in colour, and have the same lustre.
Included fragments of orthophyre and sanidinite (more acid differentiation products
of the same magma), of sandstone, and of older granulitic rocks occur in the Mount Cis
lavas. These are separately described by Mr. J. Allan Thomson.
Composition.—The mineral composition of the trachytes of Mount Cis is almost
the same in all specimens examined. Felspar forms from 60 per cent. to 75 per cent.
of the mass, and egirine-augite from 10 per cent. to 25 per cent. The balance is made
up of olivine, magnetite, leucite, sodalite, interstitial nepheline (?), analcite, cossyrite,
riebeckite, and various ferritic decomposition products, some or all of which occur
together to the extent of from 5 per cent. to 10 per cent. in all specimens. Of these
magnetite usually forms up to 5 per cent., olivine up to 2 per cent. A cossyrite-like
hornblende occasionally replaces egirine so as to form upwards of 5 per cent.
Apatite is occasionally sparingly represented in long needles. Felspathoids range
from 1 per cent. to 10 per cent. in amount.
Texture—In describing textures the nomenclature proposed by Cross, Iddings,
Pirsson, and Washington is adhered to in most instances.*
Most of these rocks have a vesicular structure, and are slightly porphyritic-hiatal
with stray phenocrysts of the first generation, most of which are discernible to the
naked eye (phaneric). The base, which forms the main bulk of the rock, is
holocrystalline, or almost so, aphanitic, extremely fine-grained (microcrystalline to
cryptocrystalline), and moderately even-grained. The fabric is usually pilotaxitic or
trachytic. In the pilotaxitic specimens the fabric becomes trachytic near vesicles,
inclusions, and xenocrysts. In texture these rocks approach closely to that of the
phonolitic varieties of Warrumbungle Mountains trachyte + (New South Wales). The
textural characters of the whole of this group of lavas from Mount Cis may be briefly
expressed thus: holocrystalline or nearly so, megaporphyritic, perpatic, mediophyric.
Inclusions.—The inclusions in the Mount Cis rocks consist of orthophyre,
sanidinites, pyroxene-granulites, diabase, and in some cases metamorphosed sandstone.
The first type is important as being autogenic, an earlier differentiation product of the
same magma; it is similar to the Australian orthophyric trachytes in texture and
composition, especially to those described by me from the Canoblas, New South Wales,
and the Glass House Mountains, Queensland.{ They consist dominantly of anortho-
clase with subordinate arfvedsonite, egirite, and egirine-augite, and occasionally
a little olivine, which is not a common mineral in Australian orthophyres. It is
interesting in this connection to note that in Australian alkaline regions this lava
type was first erupted as plugs and mamelons, the more basic varieties (dark
trachytes, phonolitic and andesitic trachytes) being erupted later, largely from dykes
and fissures. It appears that in Ross Island no sanidinitic lavas have yet been found
except as inclusions. These, however, point to the same order of succession and
differentiation as in Australia.
Minerals of the Mount Cis Rocks.—(a) The felspars are mostly of the acicular or
lath-formed habits, and consist of anorthoclase and sodasanidine. The sparing felspar
phenocrysts may have a stouter prismatic form or they may be tabular. They belong
to an earlier generation, the intratelluric period of consolidation, and usually exhibit
corrosion phenomena on the edges. They consist variously of anorthoclase,
sodasanidine, albite, and oligoclase, which are readily distinguished from one another
* Jour. of Geol., vol. xiv, No. 8, 1906.
t Proc. Linn. Soc. of N.S.W., 1907, vol. xxxii, p. 557.
t Ibid., 1909, pt. i, vol. xxxiv, and 1906, pt. i, vol. xxxi.
OF MOUNT EREBUS, ANTARCTICA 97
by their characteristic properties, such as extinction angles, refractive indices, cleavage
angles, and modes of twinning.
The microlites of the base, being of minute size, were not so readily identified, yet
the following properties point to their being anorthoclase: the refractive index was
but slightly below that of Canada Balsam, twinning was mainly on the Carlsbad plan,
but shadowy extinction of the moirée type indicated the presence of ultramicroscopic
polysynthetic twinning in some crystals, the sanidine cross cracking or parting was
fairly common, cleavage almost rectangular, and extinction angles varied from 0° to 8°
with the length of the laths.
(b) The pyroxenes consisted chiefly of egirine-augite, though in some specimens
true zgirine, and in others colourless diopside accompany the egirine-augite. The
eegirine-augite is of a greenish-yellow colour, and occurs in prismatic laths, needles,
and grains. Often a group of crystals of this mineral is optically continuous, so that the
pyroxene may be regarded as embracing the penetrating felspar needles ophitically.
The egirine-augite seems usually to have continued to crystallise out longer than the
felspar. It commonly extinguishes at angles lying between 20° and 35°, and occurs
in two generations, the earlier of which is usually less alkaline than the later.
Cossyrite-like amphiboles occur only sparingly in most specimens or not at all.
They may be scattered about in grains or form ophitic aggregates of a deep coffee-brown
colour, pleochroic from olivine-brown to deep brown opaque in sections across the length.
In some slides these amphiboles show a deep purplish-blue absorption colour on rotating
the stage, indicating affinities with riebeckite or some species of kataphorite. These
hornblendes are seldom seen with any tendency to idiomorphism, though in one slide
a few small idiomorphs were noticed. Often they form the nucleus of an egirite growth
or a fringe round magnetite. The cleavage when noticeable was at about 65°.
Riebeckite occurs only very rarely in deep blue ragged grains, sometimes frmging
cossyrite-like amphibole, or forming the nucleus of egirine-augite. Arfvedsonite is
occasionally secondary after sgirine-augite (a uralitic decomposition product),
occurring around the pyroxene (or replacing it) together with ferrite decomposition
products.
Olivine occurs only sparingly, and only as phenocrysts, which belong to the
intratelluric period of consolidation. The crystals are usually rounded grains and
have been strongly resorbed at the edges by the magma. It can only be considered a rare
or accessory constituent in these rocks.
Magnetite in idiomorphic grains is a common accessory in some of the slides,
in others soda hornblendes take its place. It is not improbable that in some of the
rocks the cubic and octahedral black isotropic grains provisionally identified as
magnetite may be a black variety of perofskite, knopite, or geikielite.
Felspathoids are not uncommon, but only present in small amounts. Usually
they are interstitial and were the last minerals to crystallise. In addition to filling
smaller interstices these minerals may form larger patches into which felspar needles
penetrate. The commonest felspathoids are sodalite and analcite.
Order of Consolidation.—There are two generations of minerals, each of which has
its own order of crystallisation. In the first generation magnetite is formed first, for
it occurs included even in the cores of olivine and pyroxene phenocrysts, and it finished
crystallising before the others commenced to separate. The olivine came next, and is
very corroded by the magma. Felspar followed, and was likewise strongly resorbed at the
rim on reaching surface conditions, and the exgirine-augite probably formed at the
same time.
As regards the second generation, magnetite and other accessories formed first,
then felspar commenced and at the same time cossyrite. Riebeckite followed, and after
98 PETROLOGY OF THE ALKALINE ROCKS
that «gerite commenced to separate. Felspar then finished crystallising, after that
egirite, which partly is later than felspar. Lastly the felspathoids formed, and occur
mainly in interstices as sodalite and analcite.
Chemical Composition.—Table I gives the analyses of pumice * from the top of
Mount Erebus and of the trachyphonolite J. 13. For comparison the analyses
are recorded of phonolitic trachyte, Cape Adare; phonolitic trachyte, Mount Terror
TABLE I.—ANALYSES OF TRACHYTIC ROCKS
A B C D E F G
Pumice, a0 .,-_ | Hornblende| Trachyandesite,
J. 13 Mt. Erebus | Phonolitic Phonolitic Trachyte, Timor Ledges,
Trachyte, Burrows | ltachyte, | Trachyte, | Ohservati Warrumbungl
Mt. Cis ( ml Cape Adare | Mt. Terror all Boe Mts, NSW.
Cumal
Phlegrose,
Substance ;
Cuma type
a a 2 :
(Hogarth) Walkom) (Schofield) (Prior) (Prior) (H. I. Jensen) (Washington)
58-94 55-95 61-01 57-95 55-47 58-95 59-79
1-40 0-98 _ 0-40 1:32 0-76 0-56
16:33 22-53 16-62 20:43 20-67 17:04 19-05
2:48 0:99 3:55 3:43 2-83 2:80 2:95
5-54 4-54 2-81 1-35 1-86 4-66 1-08
0:21 tr. 0-55 0:07 0-02 0-05 nd.
1-03 tr. 0-06 0-26 1-43 0-57 0-36
2-10 3°21 3:27 1-90 3:43 2-49 1-19
5-54 7-42 5-92 8-32 8-33 4-51 6-79
5-25 3:97 5-22 5:96 4-86 6°39 7-10
0-42 0-00 \| Loss on ig- 0-79 0-12 1-28 0-24
0-44 — f{nition1-13 0:23 0-08 0:59 —
0-57 0-02 0-07 0-03 abs. 0-10
0-05 0-06 none
0-16 : none
0:22
100-68 99-61 100°14 101-16 100-46 100:33
(Cape Crozier); hornblende trachyte, Observation Hill; and trachyandesite from the
Warrumbungle Mountains, New South Wales.
In Table VI (p. 123) the magmatic names of the rocks are given.
It will be seen that the pumice from the summit of Erebus is closely alhed in
composition to the hornblende trachyte of Observation Hill, described by Prior.
Our specimen, J.3 (1913), is almost identical with Prior’s, so that his analysis probably
represents the composition of J. 3. These rocks are closely allied on the one hand to
the tephritic trachytes, as that of Farodada, Columbretes, described by Becke { and
* The pumice analysed is the ground-mass of a very beautiful kenyte which forms the latest
lava extravasation of the present active crater of Mount Erebus. Some specimens contain abundant,
large, handsome, twinned crystals of anorthoclase.—D. M., Ed., 1916.
+ National Antarctic Expedition, 1901-4, ** Petrology.”
t Tschermak’s Min. und Petr. Mitth., 1906-7, Bd. xvi, p. 174.
OF MOUNT EREBUS, ANTARCTICA 99
placed by Rosenbusch * in the Trachydolerite group. On the other hand, the presence
of basalt hornblende, kaersuetite and high titania indicate affinities with the Kulaites.
Though so closely allied in chemical composition the Erebus pumice and the Observa-
tion Hill trachytes are very different in appearance, the former being a hemicrystalline
kenyte with huge anorthoclase phenocrysts, the latter an even-grained holocrystalline
trachyte in which only hornblende occurs as phenocrysts. The Observation Hill
trachytes are apparently kenytes in chemical composition, cf. Table I, B and E (p. 98)
with Table IT, A, B, and C (p. 110).
The Mount Cis trachyte, J. 13, is in mineral composition and microscopic structure
similar to the phonolitic trachytes from Cape Adare and Cape Crozier, of which analyses
are given for comparison. The first of these was described by David, Smeeth, and
Schofield (Proc. Roy. Soc. of N.S.W., 1895), and the latter by Prior (op. cit.). This
rock type is also akin to the phonolitic trachytes of Dunedin, New Zealand, described
by Marshall (Q.J.G.S., vol. Ixii, 1906), and the trachyandesites of the Warrumbungle
Mountains. It will also be seen that Washington’s Cumal Phlegrose is an almost
identical rock.
The Mount Cis trachyte is in the American system of classification a monzonose,
in which class the Warrumbungle trachyandesites also fall, but the margin between
these rocks and the phlegroses is very slight. High titania and the presence of some
zirconia are characteristic features of these rocks.
J. 1 (1911) is in hand-specimens a dark basalt-like rock, which nevertheless has
a silky sheen that discloses its trachytic nature. Under the microscope it is seen to be
porphyritic-hiatal in phaneric first generation phenocrysts and perpatic. The ground-
mass 1s holomicrocrystalline and varies in fabric from true trachytic near the vesicles
and inclusions to pilotaxitic away from them.
The sparing phenocrysts in this slide consist of green eegirine-augite and small
nephelines, which in this rock type antedate the felspar. The nephelines are idiomorphs,
and possess a low double refraction, a hexagonal cleavage and refractive index of 1°54.
It appears that this rock prior to its extrusion has had many nepheline idiomorphs, most
of which have changed to aggregates of sodalite and analcite. These masses preserve
the outlines of nepheline, and hence are regarded as pseudomorphous after that mineral.
The ground-mass consists of lath-shaped felspar microlites with the properties of
anorthoclase, and egirite or acmite (both with straight extinction), which occur in
hypidiomorphic prisms and allotriomorphic aggregates behaving ophitically to felspar.
Magnetite occurs as an abundant minor constituent in allotriomorphic grains ; brownish
glass occurs as a minor interstitial substance ; zircon needles occur sparingly in minute
needles in the felspars and may be looked upon as an early consolidation product.
In addition there are a few grains of deep brownish-green arfvedsonite amphibole
enveloping deep blue riebeckite grains. The latter are pleochroic from deep purplish-
black to dark brownish-green in elongated sections, and has a cleavage of 555°.
Brown cossyrite-like hornblende seems also to be present in minute amount. Sometimes
this occurs as a nucleus of sxgirine. Its pleochroism ranges from bluish-green to
greenish-brown in sections at right angles to the length of the grains.
The rock as described must be regarded as a phonolitic trachyte allied to Cumal
Phlegrose (see Washington, The Roman Comagmatic Region, p. 27).
Plate I, figs. 1 and 2.
_J. 18 (1922). This rock resembles J. 1 both in hand-specimen and under the
microscope. It contains the same felspars together with egirine-augite, egirine,
* Gesteinlehre, zweite Auflage, p. 355.
100 PETROLOGY OF THE ALKALINE ROCKS
soda-hornblendes, etc., occurring in the manner described in the previous slide. Some
of the egirite grains exhibit a tendency to uralitic alteration to arfvedsonite. The
main point of difference between this slide and the previous lies in the fact that the
former contains a considerable amount of colourless isotropic interstitial material which
is quite amorphous and frequently studded with inclusions. This has the characteristics
of nosean or sodalite, gelatinises with dilute acids and stains readily. The fabric of the
rock is pilotaxitic, and the texture may be described in general terms as holocrystalline,
megaporphyritic, perpatic, mediophyric. The specimen and slide bear close resemblance
to some pseudoleucite and nosean trachyphonolites from the Warrumbungle
Mountains. (For Analysis see Table I, A, p. 98.)
J. 27 (1936). In texture and composition this rock is very similar to J. 1 and J. 13.
It differs mainly in containing sparing phenocrysts of olivine. The yellowish-green
eegirine-augite behaves ophitically to the felspar and shows frequent decomposition to
uralitic arfvedsonite and serpentine. Ferrite is also a common decomposition product.
The dominant felspars show faint polysynthetic twinning in addition to Carlsbad
twinning under the high power, and have an extinction angle of 8°, which shows them
to be anorthoclase fairly rich in the oligoclase molecule. Several other specimens,
J. 29 and J. 30, exhibit the same characteristics in micro-section.
J. 82 (1742). This is a similar rock in texture and composition. It contains a
number of isotropic patches, penetrated by felspar laths in a stellate (divergent radial)
manner, giving parts of the slide a strahlenkérnig structure. The patches seem to
consist of sodalite. The inclusion in this specimen proved to be an olivine egirine
orthophyre or sanidinite. Another rock, J. 43,issimilar. A little nepheline and minute
interstitial crystals have also been identified in these rocks by staining methods.
All these typical Mount Cis rocks are dark and silky, vesicular, and slightly
porphyritic as viewed megascopically. Under the microscope they preserved a texture
described as holocrystalline or nearly so, megaporphyritic, perpatic, mediophyric, with
a pilotaxitic to trachytic fabric. They contain usually a fair amount of felspathoid,
which may exist as any of the minerals nepheline, nosean, or sodalite. They are
therefore trachyphonolites or phonolitic trachytes, and are all closely allied to
Washington’s Cumal Phlegrose (see The Roman Comagmatic Region, also Table I, G,
p- 98).
Other Trachytes.—Of these the most interesting types were :
J.'7 (1916). An oligoclase trachyte included in kenyte breccia from a parasitic cone
on Mount Erebus.
Megascopic characters.—Light grey compact porphyritic rock; felspar phenocrysts
about 2 mm. long of tabular and prismatic habit.
Microscopic characters (see Plate I, fig. 6).—Hypocrystalline, megaporphyritic to
microporphyritic serial, dosemic; ground-mass about 30 per cent., consisting of
anorthoclase, oligoclase, lilac augite, apatite, magnetite, other iron ores, nepheline,
cancrinite, brown glass. The fabric is of a vitrophyric intersertal type, the phenocrysts
consisting chiefly of megascopic, prismatic, and tabular oligoclase-andesine, and smaller
microscopic anorthoclase and olivine crystals, both of which species vary in size from
almost megascopic to the minute size of the nepheline augite and magnetite crystals
of the base.
Oligoclase occurs chiefly as phenocrysts which are highly corroded and which show
both optical and mechanical zoning. Twinning, Carlsbad, albite, and pericline. The
OF MOUNT EREBUS, ANTARCTICA 101
refractive index is greater than that of Canada Balsam, and the extinction angles are
those typical of oligoclase-andesine.
Anorthoclase.—Both as large and small microscopic phenocrysts with the
characteristic shape of sanidine. This felspar is less corroded and not so commonly
zoned. Its refractive index is less than Balsam, and the extinction angles agree with those
of anorthoclase. The twinning is Carlsbad, and sometimes faint lamellar twinning
accompanies It.
Augite.—This mineral is of a peculiar lilac or bistre colour, and has idiomorphic
outlines. It usually extinguishes at from 38° to 45°. Corresponds closely with the
bistre-coloured pyroxene described by J. Allan Thomson in an eclogite from Kakanui,
New Zealand. (See Geol. Mag., May 1907 ; Dee. 5, vol. iv.)
Nepheline.—Nepheline occurs as small idiomorphic crystals in the base. Secondary
cancrinite also occurs sporadically scattered in patches throughout the rock. Other
felspathoids also occur interstitially. Olivine exists as corroded phenocrysts only.
Apatite and magnetite as small crystals in the base. Secondary iron ores constitute an
important accessory. Brownish glass forms the balance of the rock.
J. 8 (1918). Kaersuetite (2), Hgirine-augite Trachyte, Observation Hill.—Megascopic
characters.—Very fine-grained aphanitic rock of dark grey colour and containing
reddish inclusions.
Microscopic characters.—Holocrystalline, even-grained pilotaxitic; consisting of
lath-shaped and acicular felspars, brown hornblendes, green soda pyroxene, and a little
opacite. Of these constituents the first two are partly microporphyritic serial, mini-
phyrie.
The felspar laths have straight extinction and appear to be anorthoclase. Green
pyroxene was last to crystallise; it occurs in grains and acicular prisms, which have
an extinction angle of 34°... A brown amphibole, pleochroic in colours from dark reddish-
brown to yellowish-brown, occurs as numerous scattered idiomorphic grains and also
as clusters of grains (Plate I, figs. 3 and 4). These clusters represent the remains of
almost completely assimilated fragments of a camptonitic rock, inclusions of which
remain in the specimen. The brown camptonitic amphibole has the properties of
kaersuetite, and this mineral has not been resorbed by the magma, but numerous
grains and microphenocrysts of it lie scattered through the base together with opacite
grains. (For Analysis see Table I, E, p. 98.)
J. 50 (1959). Baked Alkali-trachyte, Ross Island, Tuff Cone.—This specimen is
a very weathered or baked rock of reddish colour and even grain-size. It has a
microholocrystalline, pilotaxitic fabric and consists of anorthoclase, oligoclase-
andesine, iron-stained egirine-augites with an extinction of 35° in phenocrysts, (see
Plate II, fig. 6), laths, and grains, magnetite and iron ores largely secondary, and
interstitial felspathoids (nosean or sodalite).
J. 51 (997). Anorthoclase Trachyte. A compact grey specimen marked old lake
deposit.—This is typical trachytic trachyte consisting mainly of anorthoclase which
shows Carlsbad and Baveno twinning. The other minerals are interstitial rods
of «xgirine-augite (and its decomposition products, epidote, iron ores, etc.), and
idiomorphic magnetite grains. The texture is best described as holomicrocrystalline,
uneven, seriate, trachytic.
J. 62 (1961). Anorthoclase Trachyte. An erratic from Cape Royds.—This was
very similar to J. 51. Megascopically, porphyritic-hiatal in felspars of the first
Q
II
102 PETROLOGY OF THE ALKALINE ROCKS
generation. Microscopically, porphyritic-serial in felspar of the second generation,
apparently a soda sanidine. The texture of the rock is holocrystalline, mega-
porphyritic, perpatic, mediophyric, with a pilotaxitic fabric in the ground-mass. The
order of consolidation was, first magnetite, then felspar, lastly egirine-augite.
J. 52 (1466). Phonolitic Trachyte. Another erratic from Cape Royds.—This
rock is of an aphanitic appearance and vesicular in nature. It is porphyritic-
hiatal, and has a hyalopilitic base approaching strahlenkérnig intersertal. It
consists of anorthoclase, yellowish-green egirine, and dendritic and pectinate
aggregates of grains and rods of iron ore (both magnetite and hematite). Magnetite
also occurs sparingly in scattered imdependent grains, and hematite as scales. The
wegirine occurs sparingly as small phenocrysts of the first generation, and more
abundantly as idiomorphic microlites, which are commonly bunched together in
groups of parallel individuals. This pyroxene is decomposing to ferrite. Inter-
stitially occurs a colourless glassy substance, probably of felspathoid composition (see
Plate IT, fig. 5).
J. 53 (1960). Phonolitic Trachyte. Erratic from Cape Royds.—This has a texture
that may be described as microporphyritic-serial, dosemic, vitrophyric. The pheno-
crysts are equant and prismatic, consisting mainly of anorthoclase, but a fair number
of smaller phenocrysts of pseudoleucite occur in the base. The pseudoleucites
are polygonal or rounded, and consist of a mosaic of orthoclase and nepheline.
Other similar pseudospherulitic aggregates seem to consist of natrolite and to be
secondary after sodalite. The base is a greenish-brown glass, devitrifying with the
production of cryptocrystalline characters. Hence this rock is phonolitic trachyte
allied to leucitophyre.
J. 54 (1841). Anorthoclase Trachyte. Erratic from Ferrar Glacier.—This was
megascopically an extremely fine grained bluish-grey rock with phaneric phenocrysts.
Microscopically it is holocrystalline, megaporphyritic-hiatal, perpatic, and
magnocumulophyric (see Plate I, fig. 5). The phenocrysts of the first generation are
in groups, and consist of anorthoclase crystals which may envelop subordinate egirine,
arfvedsonite, and olivine. The base is coarsely microcrystalline, consisting dominantly
of an allotriomorphic granular mass of anorthoclase, the grains of which embrace
microlites of albite and egirite as inclusions, and have egirine filling the interstices
between them. ‘The structure is similar to that noticed in a Fassifern (Queensland)
Trachyte (Proc. Linn. Soc. N.S.W., vol. xxxiv, March 1909). Evidently the cause of
the peculiar fabric is that after the albite and xgirite had separated out a pasty glass
of the composition of anorthoclase was left, and this devitrified in irregular crystal
grains which embrace poikilitically the earlier form of minerals.
P. 254 (5880). Brotite Hornblende Trachyte. Erratic, Cape Royds.—The texture
of this rock is porphyritic-serial.
The phenocrysts consist of biotite and idiomorphic prismatic hornblendes belonging
to the normal brown variety, and also lath-shaped sanidine felspars. The base consists
of sanidine, greenish needles of «girine-augite, and sparingly magnetite scattered
through the rock in idiomorphic grains.
J. 21 (19380). Phonolitie Trachyte. Inaccessible Island.—This is a reddish baked
rock of hypocrystalline pilotaxitic texture. It contains large-zoned anorthoclase
phenocrysts. The other minerals are zoned anorthoclases and albites with shadowy
OF MOUNT EREBUS, ANTARCTICA 103
extinction due to strain, and Carlsbad, Baveno, and albite and Manebach twinning ;
pyroxene undergoing decomposition to ferrite and serpentine; magnetite and
ilmenite ; and much colourless isotropic glass (probably of analcite or nosean com-
position), and also a dark glass. The structure may be described as microporphyritic,
sempatic to persemic in prismatic and equant phenocrysts.
J. 16 (1925). From the same locality.—This is a holocrystalline, microporphyritic-
serial, persemic rock with pilotaxitic fabric. It consists of lath-shaped anorthoclase,
with oligoclase. egirine-augite, magnetite, and ferritic decomposition products.
J. 15 (1924). Also from Inaccessible Island.—This rock is very similarly
constituted, but contains a few megaphyric corroded olivine crystals. The texture
is hypocrystalline trachytic. The minerals are anorthoclase, oligoclase, olivine, and
eegirine-augite, with a clear colourless isotropic base probably of felspathoid
composition.
The trachytes from Inaccessible Island have in hand-specimen the appearance of
aphanitic andesite, and in mineralogical composition too they form a transition phase
between the trachyphonolites and augite andesites.
Remarks.—The felspars in all this miscellaneous series of trachyte greatly pre-
dominate in amount, forming always 80 per cent. or more of the total. Olivine is
rare or absent; magnetite is not common ; egirine is the chief dark constituent.
It is of particular interest that two types of inclusions dominate in the trachyte,
viz. sanidinite (orthophyre) in the phonoliticand orthoclase egirine trachytes and
camptonite in the oligoclase trachyte.
THE TRACHYDOLERITE AND KENYTE GROUP
The kenytes are usually considered to be a facies of trachydolerite. For the rocks of
the Erebus series I prefer to create three groups of the trachydolerite family, viz. the
Acid Kenytes, the Basic Kenytes, and the Trachydolerites proper, to be distinguished
by the nature of the phenocrysts and ground-mass, thus:
Kenytes (Acid and Basic). Phenocrysts, anorthoclase (almond-shaped), egirine.
Acid Kenytes. Phenocrysts of type; grownd-mass, structure and composition
of alkaline trachyte.
Basic Kenytes. Phenocrysts of type, also tabular oligoclase; grownd-mass,
structure and composition as in basic phonolites and tephrites. .
Trachydolerites. Phenocrysts, titaniferous augite and olivine as in dolerite;
ground-mass, structure and composition of tephritic and basanitic basalt.
The kenytes are all rough-looking rocks, varying from light grey to black in colour,
and usually markedly porphyritic in plate-like or almond-shaped felspars. They are
conveniently divided into two types: the acid type, obtained from the Skuary, Mount
Erebus, Cape Royds erratics, and Cape Barne; and the basic type, derived typically
from Turk’s Head, Mount Erebus, and Cape Royds erratics.
Composition of Kenytes.—The phenocrysts of the first generation consist of felspar,
alkaline pyroxene, and more sparingly magnetite and olivine. Rarely leucite
occurs as a product of intratelluric crystallisation. The felspar phenocrysts of
the typical acid kenytes are almond-shaped anorthoclases (as in rhombenporphyr).
and of the basic type rounded oligoclases of tabular habit. Both felspars contain
olivine, pyroxene, and magnetite inclusions.
104. PETROLOGY OF THE ALKALINE ROCKS
The pyroxene phenocrysts vary from true egirine in the most acid and alkaline
rocks of the series to a brown titaniferous pyroxene in the most basic. Both the
felspars and pyroxenes just mentioned occur also as constituents of the base and
smaller phenocrysts of a second generation.
Olivine occurs as corroded phenocrysts, very rarely as a constituent of the base.
Magnetite belongs partly to the first and partly to the second generation. Other
iron ores (hematite, limonite, ferrite, opacite) occur chiefly as secondary products.
Ilmenite frequently takes the place of magnetite.
Leucite occurs in some of these rocks as idiomorphic phenocrysts, rarely of the
first, but usually of the second period of crystallisation. It is rarely quite fresh.
Commonly it is replaced more or less by zeolites and pseudoleucite (orthoclase and
nepheline).
Other felspathoids, chiefly nosean, sodalite, and analcite, occur occasionally in the
interstices of the base.
Apatite occurs both as small first generation phenocrysts, and as a constituent of
the base.
The other minerals recorded and described under the Trachytes are also present in
variable amount, especially the soda amphiboles.
Teaxture.—The structure of these rocks is usually vesicular and always porphyritic,
namely, porphyritic hiatal, megaphyric, and usually they are dosemic, though
dopatic types do occur. The crystallinity varies from holocrystalline to
hemivitreous. The base may be anything from glassy to holocrystalline with
phenocrysts ranging from microporphyritic to magniphyric in size. The fabric of the
base may be trachytic, pilotaxitic, hialopilitic, or vitrophyric.
Inclusions.—Inclusions of a white rock determined by Mr. J. Allan Thomson to be
sanidinites and microtinites occur in some kenytes. In others (kenytic breccias on
Parasitic Cone of Erebus) we have inclusions of an oligoclase trachyte. The more
basic kenytes have frequently inclusions of the more acid types.
Order of Consolidation of the Minerals.—The minerals belonging to the intratelluric
period of crystallisation crystallised im the following order:
(a) Orthoclase in rounded fragments included in the anorthoclase phenocrysts.
This may be xenogenic in origin, the remains of partially resorbed country rock.
(b) Magnetite as grains included in phenocrysts of other minerals; and also as
independent grains.
(c) Pyroxene, both as independent crystals and inclusions in felspar.
(d) Anorthoclase as corroded almond-shaped phenocrysts.
(e) Leucite occurs occasionally as a first-generation mineral in the more basic facies
of kenyte.
All these minerals belonging to the first generation exhibit great corrosion by the
magma, and in the case of the felspars strain phenomena.
The minerals of the second generation crystallised with few exceptions in the
following order: (a) magnetite; (b) olivine; (c) apatite; (d) titaniferous pyroxene
and wxgirine-augite; (e) felspar; (f) wgirite, glass, and felspathoid.
Habit of Felspar.—The felspar of the kenytes consists of three kinds :
(1) Almond-shaped corroded anorthoclase crystals, grading into microcline
microperthite, and moirée microcline ;
(2) The idiomorphic prismatic and tabular soda sanidine or anorthoclase of the
base; and
(3) The tabular corroded phenocrysts of acid plagioclase in many of the basic
kenytes.
OF MOUNT EREBUS, ANTARCTICA 105
The anorthoclase phenocrysts are often zoned both optically and mechanically,
the former being due to varying composition, the latter a corrosion effect. They show
good Carlsbad twinning usually combined with cross-hatching due to fine lamellar twin-
ning in directions which cannot be assigned definitely to any of the common twinning
laws (see Plate II, fig. 3).
The ground-mass felspar seldom shows this fine twinning, though occasionally it has
distinct albite and pericline twinning, as well as Carlsbad. The plagioclases are likewise
frequently zoned, and have well-marked Carlsbad, albite, and pericline twinning.
They belong chiefly to the oligoclase species, though they may range to the basicity of acid
labradorite.
The other minerals have already been described to a sufficient extent.
2. GROUP OF ACID KENYTES
General Characteristics.—Hand-specimen, light grey to reddish with large felspars,
forming about half the mass. The texture and general composition have already
been indicated. The large anorthoclase and microcline microperthite phenocrysts,
forming from 30 per cent. to 50 per cent. of the mass, have in addition to the properties
already mentioned a refractive index very near that of Canada Balsam; their peculiar
microperthitic and polysynthetic twinning only become visible near the position of
extinction: included in them we have rounded quartz and orthoclase grains, apatite,
olivine, magnetite, pyroxene shreds of glass and iron ores.
The other phenocrystalline minerals are, wgirine and egirine-augite, which are
usually uncorroded, but sometimes slightly resorbed; magnetite in idiomorphic or
more or less corroded crystals; apatite in stout diomorphic rods ; olivine in corroded
grains. The base varies from holocrystalline, either pilotaxitic (strahlenkérnig) or
trachytic, to hypocrystalline (hyalopilitic), hemicrystalline (vitrophyric), and
holohyaline. -The minerals of the base are often porphyritic-serial, and consist of
felspar microlites, «egirine, soda amphiboles, apatite, magnetite, and glass. In a few
cases colourless felspathoid or other isotropic material which gelatinises with dilute
acid is also present; this may be sodalite, nosean, or analcite; the analyses indicate
a frequent abundance of nosean.
The most typical acid kenytes were got from the Skuary.
J. 47 (1956). The Skuary.—Hand-specimen, grey, rough with coarse crystals.
Texture.—Porphyritic hiatal in phaneric rhomben-felspars, sempatic, magnophyric.
The base is holocrystalline, pilotaxitic, approaching panidiomorphic granular or
diabase structure.
Composition.— Anorthoclase of the habits described above forms about 35 per cent.
in phenocrysts, and 35 per cent. of the rock in the base. The phenocrysts contain
numerous included zircon needles. They have each a dark zone near the rim, consisting
of included granules of the materials of the base, and into this zone the crystals of
the base often project. The phenocrysts are highly resorbed and rounded by corrosion,
yet of very large size, reaching a length of half an inch.
Magnetite, olivine, apatite, and pyroxene occur in the manner described under
general characteristics. The pyroxene phenocrysts consist of sgirine-augite of
greenish colour, faint pleochroism and high extinction angle (38°).
The base is a pilotaxitic mass consisting of felspar laths, with Carlsbad and some-
times very faint lamellar twinning, probably anorthoclase; acicular prismatic
microlites of egirine-augite similar to that of the phenocrysts; laths of a brown
hornblendic mineral which is pleochroic from deep brown along the length to opaque
106 PETROLOGY OF THE ALKALINE ROCKS
transversely (species of cossyrite); idiomorphic grains of magnetite; apatite and
zircon needles and a little interstitial dark glass. The base is therefore like the
trachyte of Observation Hill, Hut Point, though the brown hornblende is most
nearly allied to that of the Cape Crozier trachyte described by Prior (cf. Table I,
D and HE, p. 98).
J. 25 (1984). Vitrophyric Kenyte (Analysis, Table IT, C, p. 110), same locality —Hand-
specimen, reddish.
Teature.—Coarsely porphyritic, dopatic, megaphyric with vitrophyric fabric, the
base being almost holohyaline.
Composition.—The chief constituents are lozenge-shaped anorthoclase (microcline
microperthite) phenocrysts, some egirine phenocrysts (Plate IT, fig. 4), and red glass.
The latter constituent fills corrosion cavities in the phenocrysts (Plate II, fig. 3).
The other phaneric minerals are corroded lumps of magnetite and smaller grains of
red iron ore. The red glassy base contains some microporphyritic laths of anorthoclase
and non-refracting cryptocrystalline needles (belonites) immersed in the reddish-yellow
tachylitic matrix.
J. 5 (1712). Kenyte, same locality.—This rock is similar to J. 47, but more
coarsely grained, quite holocrystalline, and contains some secondary epidote
replacing the original egirine-augite to some extent, and also aggregates of dusty
soda hornblende. Interstitially colourless idiomorphic material consisting of nosean,
and full of riebeckite inclusions, is present.
For Analysis see Table II, B, p. 110.
J. 40 (1948). Kenyte, same locality.—Very similar to J. 47. It differs from J. 47
chiefly in the greater abundance of olivine phenocrysts, and in the greater alkalinity
of the pyroxene, which is here a true egirine. The base is_holocrystalline
stahlenkornig. It differs from J. 47 in the absence of cossyrite-like hornblende, and
the presence instead of scattered grains of a purplish opaque, very pleochroic
hornblende, which changes colour from dark blue opaque to purple on sections
parallel with the length, and reddish-brown opaque on sections at right angles to the
length. This amphibole is probably a kataphorite closely allied to riebeckite.
Flakes of hematite are abundant in this rock. This specimen is clearly of a more
alkaline type than those already described.
Photo. Plate II, figs. 1 and 2.
J. 63 (1962). Specimen P. 103. An erratic from Cape Royds.—Similar to the
foregoing. Kenytes of the acid type were also obtained on Mount Erebus, at Cape
Barne, and as erratics at Cape Royds. Many Cape Royds erratics correspond closely
with the Skuary types. Decomposition of the xgirine to epidote and the formation
of secondary magnetite were noticeable features.
The typical Mount Erebus and some Cape Royds kenytes are different from those
just described (see Plate III, fig. 1). They occupy a position intermediate between
the Skuary and the Turk’s Head types. The phenocrysts are those of the acid kenytes,
and the base is that of the basic kenytes and tephrites. The phenocrysts consist of
the characteristic rhomben felspars, sparing olivine, pyroxene, ilmenite, and sphene.
The base is hypocrystalline, microporphyritic serial, hyalopilitic, and consists of
miniphyric phenocrysts of leucite (with characteristic outlines, central and marginal
inclusions of dusty magnetite), microlites of felspar, brown glass, and colourless isotropic
glass (possibly of the composition of nosean, sodalite, or analcite). The brown glassy
OF MOUNT EREBUS, ANTARCTICA 107
material contains minute magnetite needles (incipient skeleton crystals), and brownish
belonites of titaniferous augite just commencing to devitrify out of the glass.
Pyroxene belonites and glassy felspathoids were clearly the last products of
consolidation.
The leucites possess the characteristics of the leucite from the Cape Royds kenyte
described by Dr. G. T. Prior*; they are often feebly birefringent because of
alteration to pseudoleucite. The felspar microlites consists of anorthoclase.
Prior gives an analysis and photo of a similar specimen. For Analysis see A,
Table II, p. 110, or Analysis No. 3, p. 119, vol. 1, National Antarctic Expedition of
1901-1904. For illustration see Plate III, fig. 1, and Plate VIII, fig. 3, National
Antarctic Expedition, 1901-1904, vol. 1.
J. 64 (1963), P.54. Half-way between Cape Royds and Cape Barne, one mile south
of Back-Door Bay.—This rock is similar to the Erebus specimen, but contains some
titaniferous pyroxene phenocrysts.
P. 55.—This is also very similar to the Erebus kenyte. The pyroxene of the first
generation is a titaniferous «girine-augite, and the base contains abundant leucites.
The specimen exhibits striking similarity to the kenyte from Cape Royds examined
and analysed by Prior.
J. 44 (1958). Kenyte, Turk’s Head.—This is a dark grey, almost black, somewhat
porous lava, porphyritic in large phaneric crystals of felspar with almond shape. These
crystals are very dark in colour from abundant inclusions. The hand-specimen is very
like the Erebus type just described.
Texture.—P orphyritic, sempatic, magnophyric in anorthoclase of the first generation.
The base is hemihyaline and hyalopilitic.
Constituents.—The phaneric felspars are of the species of microcline-microperthite.
Apatite, magnetite, olivine, and egirine also occur as representatives of the first
generation. The base is quite isotropic under the low power, but the high power
reveals felspar microlites, brown grains and belonites whose nature cannot be deter-
mined, and yellow glass.
J. 48 (1957). Vuitrophyric Kenyte, Cape Barne.—This rock is very similar to
J. 25 from the Skuary. The almond-shaped microcline-microperthites studded with
inclusions are of the typical habit and kind. The base is vitrophyric tachylite, and
contains corroded phenocrysts of magnetite, olivine, and xgirine-augite; also rods of
apatite and microlites of a sanidine-like felspar. (See Plate II, fig 4.)
3. THE GROUP OF BASIC KENYTES
General Characteristics.—Phenocrysts, anorthoclase and acid plagioclase; base,
phonolitic or tephritic. The hand-specimens of oligoclase kenytes show the tabular
plagioclases to possess a planophyric arrangement.
Excepting for the presence of plagioclase in lieu of microperthite phenocrysts, and the
oreater abundance of felspathoid, the minerals are the same as those of the acid kenytes.
The fabric is as variable as in the previous group, but there is a stronger tendency
for the base to remain glassy.
All members of this group contain abundant macroporphyritic phenocrysts of
felspar, and smaller amounts of corroded augite, olivine, and magnetite visible to the
* National Antarctic Expedition, 1901-1904, Natural History, vol. i, ““ Geology.”
108 PETROLOGY OF THE ALKALINE ROCKS
naked eye. They are mostly sempatic, the large phenocrysts amounting to from
40 to 60 per cent. of the mass.
Rocks of this type come chiefly from Turk’s Head, Cape Royds, and the Dellbridge
Islands.
J.11 (1920). Plagioclase Kenyte, Turk’s Head. (See Analysis D, Table II, p. 110.)—
This is a grey rock with very large tabular phenocrysts, the thicker of which are
occasionally made almond-shaped by corrosion.
Texture.—Megaporphyritic, sempatic, magnophyric. The grey aphanitic base is
pilotaxitic, and varies from micro- to erypto-crystalline. (See Plate III, figs. 2 and 3.)
Constituents.—The most abundant constituent is plagioclase of the species
oligoclase, often surrounded by a zone of albite or anorthoclase. This occurs only
as phenocrysts. The other phenocrystalline minerals are olivine, magnetite, and brown
titaniferous augite in corroded grains, and stout rods of apatite. The pyroxene has
an extinction angle of 25°, and is probably a titaniferous sgirine-augite.
The base is practically holocrystalline, the only isotropic constituent being a clear
colourless interstitial residuum, which probably consists of analcite or sodalite together
with some nosean as indicated by analyses. The other constituents are :
(1) Felspar laths with Carlsbad and fine lamellar twinning, and the refractive
index near that of Canada Balsam, probably anorthoclase.
(2) Aigirine-augite in minute stunted rods and grains.
(3) Black grains of magnetite.
(4) A few idiomorphic nephelines.
(5) A brown barkevicitic hornblende in scattered grains, and also in mossy
aggregates, composed of minute rods.
(6) Allotriomorphic leucite crystals with characteristic inclusions.
(7) A few riebeckite grains.
Of these constituents the felspar is predominating in amount.
This rock, which may be termed oligoclase-kenyte, is closely akin to the
anorthoclase-kenyte (J. 44), though in macroscopic structure and appearance there is
a notable difference, especially in the habit of the porphyritic felspars.
J. 55 (500), P. 66. Erratic, Cape Royds.—Texture——Porphyritic serial and
glomeroporphyritic serial, sempatic, minophyric. The base is a hemicrystalline,
decomposed, vitrophyre.
Constituents.—Oligoclase in small phenocrysts, still smaller phenocrysts of
magnetite with hematite and limonite as decomposition products, light brown
titaniferous augite with an extinction angle of 34°, very corroded grains of enstatite,
hematite secondary after a brown basaltic hornblende, and a few idiomorphs of nepheline.
These form the phenocrysts; the base is very decomposed, and contains abundant
felspar microlites and skeletons of secondary iron ores. Felspathoid minerals appear
to have been originally present.
This rock has close affinity with phonolitic oligoclase trachyte, and with the
Kulaites described later.
J. 46 (1955). Kenyte Agglomerate, Turk’s Head.—A dark fragment in the agglomerate
was sectioned. It was serial porphyritic in oligoclase of prismatic habit, and with
Carlsbad, albite, and pericline twinning. Optical anomalies, such as shadowy
extinction, occur in the phenocrysts, and are due to strain. Small olivine phenocrysts
are also present. The base is mostly non-crystalline, and consists of innumerable dusty
OF MOUNT EREBUS, ANTARCTICA 109
magnetite grains in a colourless glass. A number of black and brown opacite masses
suggest the origimal presence and subsequent disintegration of hornblende.
Another fragment in this rock is a black vitrophyre containing phenocrysts of
oligoclase magnetite and augite in a black opaque matrix.
No. X. Shonkinitic Kenyte Porphyry, erratic, Cape Royds.—This rock is a remark-
able kenyte im which the phenocrysts are those minerals which constitute the usual
constituents of teschenite and shonkinite, while the ground-mass is a normal trachyte.
The phenocrysts are :
(1) Labradorite felspar with extinction angle 30° corroded at the same time in the
centre and around the rim.
(2) Bistre-coloured to purplish augite in small slightly corroded phenocrysts
sometimes surrounded by a corrosion rim of magnetite.
(3) Large corroded phenocrysts of brown basalt hornblende with sapphire (?)
inclusions. In many cases the whole or a large part of the hornblende is pseudomorphosed
to magnetite, usually with a core of hypersthene.
(4) Broken nepheline crystals and pseudomorphous aggregates of orthoclase and
sodalite after nepheline.
(5) Groups of large idiomorphic soda orthoclase crystals. Veins consisting of an
intermixture of orthoclase and fluorspar traverse the rock.
The ground-mass consists of a very fine-grained holocrystalline base of anorthoclase
egirine-augite, riebeckite, and dusty magnetite in isometric grains and stunted rods.
4. GROUP OF TRACHYDOLERITES
The name trachydolerite is most suitably retained for those rocks which have the
phenocrysts of porphyritic basalt or dolerite, and a ground-mass of a tephritic nature.
Texture.—T hese rocks have porphyritic, megaporphyritic structure, and are usually
vesicular. The phenocrysts may be serial or hiatal. The ground-mass is a variable
from holocrystalline to glassy, with fabric ranging from pilotaxitic, doleritic, ophitic
or strahlenkérnig to hyalopilitic or vitrophyric.
Composition.—(1) Phenocrysts.—Olivine occurs in abundance as large corroded
crystals. Titaniferous augite, often enveloped by an outer zone of secondary
deposition, is also abundant and attains large size. Apatite and magnetite or ilmenite
occur as smaller phenocrysts, the former idiomorphic, the latter corroded. Enstatite
is not infrequent. Large felspar phenocrysts, ranging from oligoclase to basic
labradorite, may be present.
(2) The Ground-mass——The base consists of acid plagioclase, anorthoclase,
magnetite, purplish augite, more rarely green xgirine-augite, felspathoids, and glass.
The characters which all these minerals present are so typical as to need no further
description. The order of consolidation is the normal one for dolerites. The pyroxene
may precede or follow the felspars.
In hand-specimen these rocks all resemble porphyritic basalt. They are very dark,
almost black, in colour, and very rough in fracture from the unevenness of the grain size.
J. 12 (1921). Trachydolerite Breccia. Parasitic cone on Erebus.—Hand-specimen.—
Typical breccia with large and small fragments of lava.
Micro-structure.—The section includes portions of both the fragments and the tuffy
base.
Teaxture.—The inclusion is a porphyritic serial, vitrophyric trachydolerite, with a
Il R
110 PETROLOGY OF THE ALKALINE ROCKS
pilotaxitic flow arrangement in the microphenocrysts; sempatic; mediophyric to
miniphyric. The tuff portion has typical aschen-structur. (Plate III, fig. 4.)
Included fragment. This contains large first-generation phenocrysts of acid
labradorite, and smaller corroded phenocrysts of titaniferous augite, olivine, apatite,
and magnetite. All these range in size from phaneric to aphanitic. Smaller
patches of isotropic material possess the characteristic form and inclusions of leucite.
The base contains felspar laths with the properties of anorthoclase forming one-third
of its bulk, and the remainder consists of glass. The tuff portion of the slide contains
the same kinds of mineral.
The rock is therefore a leucitic trachydolerite.
J. 56 (1124). This is a somewhat similar rock to the inclusion in the pre-
ceding. It is, however, megaporphyritic hiatal, dopatic, hyalopilitic. The acid
labradorite phenocrysts of this rock are frequently surrounded by a deposition of
magnetite belonging to the effusive period of crystallisation.
J. 41 (1950). Trachydolerite, Inaccessible Island.—This rock is similar. The felspar
phenocrysts are somewhat more acid, being oligoclase andesine, and a little biotite is
present.
TABLE II. ANALYSES OF KENYTES
A B C D 1D)
J. 25 ini Dunklere altere
Ke Ais ay ee Aufscheidung,
enyte, ikenvie Vitrophyric Plagioclase ephntie
Substance C. Royds The Sian Kenyte, Kenyte, Tina
(Prior) (Ho; arth). The Skuary Turk’s Head Galumbretes
oe (Hogarth) (Hogarth) vide Rosenbusch
55-62 54-84 47-56 46-39
1-35 1-34 2-60 0-72
19-07 18-57 18-77 19-03
6-06 6-26 1-66 9-79
nil 0-47 7-13 0-96
0-20 0-21 0-20 a
1-20 1-06 2-82 5-33
2-72 3-00 7-82 7-02
7-56 6-96 5-15 5-47
4-59 4-51 2-68 2-47
0-12 1-20 1-27
0-14 0-62 0-82 2-04
0-47 0-85 0-07 0-88
0-03 0-05 trace
0-97 0-56 0-06
0-15 0-20
abs.
0-28
Sum
OF MOUNT EREBUS, ANTARCTICA 111
The close relationship of the normal kenytes to the hornblende trachytes of
Observation Hill has already been referred to. The analyses of the Skuary kenytes
are of interest as being of rocks almost devoid of ferrous iron. In J. 5 (Table I, B,
p- 110), magnetite must be absent; the dark grains resembling magnetite must be
riebeckite. J. 25 (Table II, C, p. 110) is also a riebeckite-bearing rock. The norm of
both these rocks (see Analyses IV and V, Tables V and VI, pp. 122, 123) indicates
presence of both nephelite and noselite molecules. The kenytes differ from the trachytes,
as regards chemical composition, in the following respects: they contain less silica,
more alumina, more lime, and more phosphoric acid. Zirconia is usually present.
The rocks here designated plagioclase kenytes are of a much more basic nature.
Tron minerals are more plentiful, also magnesia. In alkali percentage as well as
general composition they correspond to the Tephrites and Basanites of Rosenbusch,
but the texture is so typically that of the kenytes that it is as well to regard them as
a basic kenyte. The norm gives their position in the American classification as being
in the subrang Salemose, which brings out relationships with camptonite from Maine,
nephelite basalt, dolerite and other rocks (cf. Chemical Analyses of Igneous Rocks,
by Washington, Professional Paper No. 14, U.S. Geol. Surv.). The basic inclusions
in tephritic trachyte, Forodada, Columbretes, are almost identical in chemical com-
position with the plagioclase kenyte (cf. Analysis 36, p. 355, Gesteinlehre, 2nd ed.).
This is additional evidence that this rock type isa basic differentiate of the kenytic
magma.
5. THE GROUP OF LEUCITOPHYRES AND TEPHRITES
In hand-specimens these rocks resemble dark grey or reddish-brown basalts.
Vesicles are often arranged in a planophyric manner.
Texture.—Porphyritic hiatal or glomeroporphyritic; sempatic; meduphyric to
mediophyric. Vesicles abundant or absent: fabric of base, hypohyaline, pilotaxitic,
occasionally ocellar.
Constituents.—The constituent minerals are those of the trachydolerites, but leucite
is relatively much more abundant, forming one of the chief constituents, and felspar is
less abundant. Leucite occurs as mediophyric and minophyric phenocrysts, which
are frequently altered to pseudoleucite. The other phenocrysts attain a smaller size.
J. 57 (1499). Leucitophyre.—The chief crystalline constituents of this rock are
tabular oligoclase-andesine crystals, idiomorphic leucites and pseudoleucites, and
corroded prisms of egirine-augite. The base consists mainly of red glass, which
contains fine microlites of felspar and egirine-augite.
This rock is therefore an oligoclase leucitophyre. (Plate IV, fig. 6.)
The other leucite-bearing rocks are of a more basic character, and belong rather
to the group of tephritic basalts.
J. 31. Leucite Tephrite. Loc.: Top of Crater Hill.—This is a reddish porous
rock, the vesicles of which are arranged in planes or bands. The core of the specimen
is dark basaltic-looking, and has small leucite and nosean phenocrysts of minophyric
size studded through the aphanitic base. The leucites are, under the microscope, seen
to be altered to a mosaic of orthoclase and nepheline (pseudoleucite), and vary in size
from just megascopic to microscopic (minophyric to miniphyric). Their rounded
outlines are due to resorption. Other corroded microscopic phenocrysts are present
in ragged grains composed of olivine, light brownish hypersthene secondary after
hornblende, idiomorphic cumulophyres of uncorroded augite with hour-glass twinning,
and large corroded magnetite grains.
112 PETROLOGY OF THE ALKALINE ROCKS
The pseudoleucite and nosean crystals contain inclusions of black magnetite and of
honey-yellow to deep brown wohlerite. (Plate IV, figs. 3 and 4.)
The base is a miniphyric vitrophyre consisting of colourless glass in which minute
needles of alkali-felspar, microlites of titaniferous augite and dusty magnetite are
scattered broadcast. The texture of this rock is porphyritic serial in leucite and
nosean with ocellar fabric. From the chemical composition the colourless glassy
material of the base should have the composition of nosean.
6. CLASS OF BASALTS POOR IN OLIVINE
These rocks possess the usual textures and mineral composition of basalts. Cape
Barne was a particularly prolific source of them. They vary from fine-grained to
aphanitic in grain size.
J. 6 (1915). Intersertal Augite Andesite, Cape Barne.—Hand-specimen.— Vesicular
brownish rock with the appearance of andesitic basalt, no phaneric phenocrysts.
Microscopic Texture-—Porphyritic serial in felspar which is regularly distributed
in prismoid and equant microscopic phenocrysts, consequently very uneven- grained ;
hypocrystalline with intersertal fabric tending towards ophitic, groups of augites being
present which extinguish together. The phenocrysts consist of oligoclase, but the
smaller laths seem to be anorthoclase, the composition of the felspar varying between
these two according to the size of the crystals. The other minerals are idiomorphic
magnetite grains, a few stray olivines, hypidiomorphic grains and rods of brown
titaniferous augite and interstitial glass.
The pyroxene was the last mineral to crystallise. The position of this rock is
intermediate between trachyte, andesite, and basalt.
All the other basalts poor in olivine are likewise from Cape Barne.
J. 2 (1912). Aphanitic vesicular rock with ocellar structure.—Teature.—
Hypocrystalline, hyalopilitic. (See Plate V, fig. 3).
Constituents.— Labradorite in laths, 50 per cent.
Faint brown augite and brown glass, 40 per cent.
Magnetite, 7 per cent. Olivine, 2 per cent. Apatite, 1 per cent.
J. 4 (1914) is a similar rock, but contains slightly more olivine. (See Analysis, Table
III, D, p. 114, and Table V, No. X, p. 122.)
J. 10 (1919). This rock has a higher felspar percentage, and has numerous prisms
of olive-brown to reddish-brown hypersthene interspersed with the augite laths and
magnetite of the base. Phenocrysts are rare, but dark patches of opacite occur, which
are decidedly suggestive of derivation from basaltic hornblende. The hypersthene
of the base also points that way.
J. 58 (1858). This rock is intermediate between J. 4 and J. 10.
J. 19 (1928). Texture.—Microporphyritic serial, vitrophyric, with vesicles shaped
and arranged so as to give an ocellar structure to the rock.
Composition.—This rock differs from those just described mainly in containing
a higher percentage of magnetite and black glass. Small olivines are sparingly present,
and are highly corroded. Brownish augite occurs as small phenocrysts in the
devitrifying base.
OF MOUNT EREBUS, ANTARCTICA 113
Various irregularly shaped dark patches profusely rich in magnetite represent
either disintegrated xenoliths or the degradation products of basaltic hornblende.
In J. 20 (1929), a very similar rock, the fine dusty magnetite of these dark areas
was clearly seen to be imbedded in a brownish isotropic matrix. The magnetite is clearly
of secondary origin, and it seems most likely that these rocks originally contained basalt
hornblende.
J. 24 (1983). This is a microporphyritic serial basalt without olivine, the
phenocrysts being a basic labradorite. In this slide, too, occur black augite-opacite
ageregates secondary after hornblende. The base is intersertal, almost panidiomorphice,
hypocrystalline, consisting of felspar in needles, augite prisms, magnetite grains and
apatite in stout rods, with a trace of interstitial glass.
The majority of the olivineless basalts have, it will be seen, the following general
characters :
(a) Felspar, usually basic labradorite, forms 50 per cent. of the bulk or less.
(6) Black patches crowded with dusty magnetite inclusions probably represent
disintegrated hornblende phenocrysts.
(c) Olivine is only sparingly represented.
(d) Apatite is less abundant than in the kenytes.
(e) The glassy base consists largely of dark brownish-black glass undergoing
devitrification to magnetite, titaniferous pyroxene and hypersthene. It is full
of black magnetite grains both of primary and secondary origin.
(f) No felspathoids detected in this group.
7. THE GROUP OF OLIVINE BASALTS
The general characters of this group are so well known as to need no detailed
description. The peculiarities of the Antarctic olivine basalts examined by me seem
to be that they are usually coarsely porphyritic, and approach the limburgites on the
one hand and the basanites on the other. Felspathoid minerals are of common
occurrence as a minor constituent. The felspar of these rocks consists of basic
labradorite, and the pyroxene is a deep brown titaniferous augite. The olivine is
usually in large corroded phenocrysts. Felspar does not usually occur as phenocrysts,
but may do so in some types. The texture is usually holo- to hemi-crystalline,
porphyritic hiatal, dopatic or sempatic, megaphyric, and the fabric hyalopilitic.
J. 59.—Porphyritic Felspar Olivine Basalt, Cape Royds.—This rock is a black
porphyrite full of tear-shaped vesicles (drawn into that form by flow during the plastic
condition).
The phenocrysts consist of basic labradorite, olivine, highly titaniferous augite,
magnetite, and apatite. The holocrystalline pilotaxitic base consists of acid
labradorite in laths, and augite and magnetite in idiomorphic grains.
J. 28 (1987). Enstatite-olivine Basalt or Basanite,loose block, foot of Crater Hill.—
Texture.— Porphyritic serial, dopatic, mediiphyric. Ground-mass holocrystalline, inter-
sertal. '
Constituents.—Felspar, consisting of acid labradorite, occurs only as laths and
microlites of variable size belonging to the effusive period of crystallisation. The
olivine and enstatite form corroded microphenocrysts belonging to the intratelluric
114 PETROLOGY OF THE ALKALINE ROCKS
period. The intersertal base consists of a granulite mass of brown titaniferous augite
and magnetite in almost idiomorphic grains, giving the whole rock almost a panidio-
morphic structure. A little interstitial, colourless, and isotropic material is present,
probably sodalite or analcite.
J. 26 (1985). Limburgitic Basalt, Hut Point.—Texture.—Microporphyritic hiatal,
dopatic; hyalopilitic fabric near to diabase structure.
Composition.—Magnetite forms about 30 per cent., titaniferous augite about
45 per cent., and alkali-felspar about 15 per cent. These minerals belong to the second
generation, and in the interstices between them we have fillings of analcite or sodalite.
About 10 per cent. of the rock consists of olivine in small hypidiomorphic phenocrysts.
Nepheline also appears to be present.
The rock is a very basic one, and may be called limburgitic basalt allied to basanite.
Two rocks, viz., J. 49 from Cape Barne and J. 36 from Mount Bird, are allied to
kulaite, but must be put in this group as felspar olivine basalts.
J. 49 (1958), Cape Barne. This is a black rock, porphyritic in white phaneric
felspars.
Texture.—P orphyritic hiatal, sempatic, megaphyric, with aphanitic hyalopilitic base.
TABLE III. ANALYSES OF BASIC ROCKS
A B C D E EF G H
bm 2 o Ss
Base | GR oSlBsgSs|/ 5808) Sot | Bane 2h | Sods
PGES EL ESSSE 358) eon | FSS | eaSo| See | snes
=e nae” |2 ess & aoe e oa go- | B.Sm
mS e 4 Z
gio, . . .| 43-92 | 45-63 | 48-29 | 43-54 | 42-14 | 42-10 | 41-64 | 40:53
TiO, Pray eae 2-42 = 5-03 | 4:90 | 4-93 4-36 1-80
Al,O, . . .| 17-42 | 10-43 | 10-00 | 16-08 | 14-95 | 14-87 | 13-80 | 14-89
evO Se le. el 8-09 1:20 | 2-93 2-63 2-90 | 3-26 7-93 1-02
MeO ee «oll ABU M[SOBal Uber), Mole |. W971 9-76 5-41 | 11-07
MnO ee) edly 00917) 9017 = 0-20 | 0-12 | 0-07 0-19 | 0-16
MeO) 4. 3!| 489. | A501 || 17-22 6-44 | 9-47 8-88 8-78 8-02
Gio © . | 953 | 12-89 |. 11-80 | <8.09-) 10:32 | 10-63 |) 11-16)" 1462
Nao: 2 2a) 4:60 2-04 2-78 3-61 3-27 3-20 | 2-14 2-87
KeOn eee a inoaly 0-74 0-45 1-67 1:80 1:80 1-40 1-95
MoO Gos) .| 0-11 0-16 ) 0-36 | 0-16 | 0-12 | 0-47
H,0 (100°=),. .|| ©-0¢ | [0-21 J) *%? | 008) O12 |) O41 )) 62 } 1-44
PO, eee. ctu 50-67 0-43 = 1:29 | 0-40 | 0-58 0-96 1:32
CO, Pal nya 0-12 = 0-15 = — 0:05 | 0-17
SO, Zt = a se = = 1:70 =
Zn0, = Ss = = ae = abs =
NiO.CoO = = = = = ans i =
BaO — — —— — — — abs =
SrO = = a 1-46 a = = as
Li,O — — — _ — —- abs _o
Cl = = = = = = = =
Sum . . | 100-57 | 100-38 | 100-88 | 100-77 | 100-26 | 100-31 | 100-61 | 99-86
OF MOUNT EREBUS, ANTARCTICA 115
Composition.—The phenocrysts consist of oligoclase, usually exceeding 5 mm. in
size, titaniferous augite 3 to 4 mm., smaller olivines and magnetite. Black opacite
pseudomorphous after hornblende also occurs (see Plate V, fig. 2), and are of mega-
porphyritic size. The base is hemicrystalline and consists of anorthoclase microlites,
brownish idiomorphic grains of titaniferous pyroxene, magnetite grains, and a yellow
devitrifying glass studded with inclusions. There are also colourless isotropic areas
studded with inclusions, and they have probably the composition of nosean or analcite.
J. 36 (1944), Mount Bird.—This is described in the section dealing with Cape Bird
rocks (post, p. 125).
Both the basalts rich in olivine and the limburgites described hereafter are similar
to the olivine basalts and limburgites described by David, Smeeth, and Schofield in
Proc. Roy. Soc. N.S.W., vol. xxix, 1895, and those described by Prior in the National
Antarctic Memorr.
Chemical analysis shows that the basalts from Cape Barne and, in fact, all the
basaltic rocks of Ross Island differ from normal basalts and can be divided into two
classes, one of which has limburgite affinities, the other of which contains hornblende
or pseudohornblende phenocrysts and is related to the Kulaites (Table IV, p. 120).
The olivine basalt from Cape Barne, J. 4, is a typical member of the second group, and
one which does not display its affinities by pseudomorphs after hornblende. The
felspar molecules (see Table VI, p. 123) (high alumina) are sufficiently abundant to place
this rock in the Salfemane class, while the typical limburgitic basalt has a lower Al,O,
percentage, and belongs to the class Dofemane.
J. 10, J. 19, and J. 20 are basalts similar to those described by Prior from Sulphur
Cones, and his analysis (Table III, A, p. 114) gives their composition approximately.
Their relationship to Kulaite is evident both from mineral and chemical composition.
The analysis of J. 4 corresponds closely with Prior’s olivine basalt from the Gap
and his limburgitic basalt from Winter Quarters.
The leucite tephrite, Crater Hill (see J. 31, also Analyses G, Table HI, p. 114, and XI,
Tables V and VI, pp. 122 and 123), is allied to the limburgite J. 68 (see Analysis B,
Table III) on the one hand and to the basanites on the other. The amount of sulphuric
anhydride in the rock is very large, and shows that much of what was originally con-
sidered leucite is in reality nosean. The norm (see Table VI) differs remarkably from the
mode, especially in the development of felspathoid in place of felspar.
The normative composition of the limburgite, J. 68 (Table VI, No. IX, p. 123) bears
out the microscopic determination of the remarkable pseudomorphous aggregates after
felspar. It is a typical Kossweinose, as a comparison with the analysis of the Rosswein
type rock (Table IIT, C, p. 114) shows.
8. GROUP OF THE LIMBURGITES
In this group felspar is absent, or only subordinate in amount. They closely
resemble the porphyritic basalts in hand-specimen, and are usually coarsely
porphyritic in olivine and augite. The pyroxene is generally of two generations. The
order of consolidation was normal.
The usual texture is porphyritic hiatal, sempatic, magnophyric with intersertal
base, which may be hyalopilitic, diabasic, or strahlenkérnig (divergent radial).
J. 60 (528 ?). Limburgitic Basalt.—Texture.—Porphyritic hiatal, dopatic, magno-
phyric ; ground-mass diabase grained.
116 PETROLOGY OF THE ALKALINE ROCKS
Composition.—The phenocrysts are corroded olivine, enstatite, magnetite, and a
few idiomorphic labradorites full of magnetite inclusions. The base, which is almost
panidiomorphic in structure, contains brown titaniferous augite in prismatic grains,
magnetite, and a smaller amount of basic labradorite microlites.
J. 9 (1918). Limburgite, Observation Haill.—Teature.—Microporphyritic _ serial,
dopatic, magnophyric.
Fabric.—Intersertal, diabase structure.
Composition.—T his rock consists of hypidiomorphic grains of titaniferous pyroxene
(about 50 per cent.), labradorite microlites (about 35 per cent.), idiomorphic magnetite
(about 10 per cent.), and olivine in microscopic phenocrysts (about 5 per cent.).
J. 28 (1982). Basanitic Limburgite, Cape Barne.—This is a similar rock toJ. 9, but
more deficient in felspar, which amounts to less than 20 per cent.
Texture.—Porphyritic hiatal, dopatic, panidiomorphic.
Composition.—Magnophyric phenocrysts of olivine and hypersthene imbedded in a
base consisting of titaniferous augite, very basic plagioclase, magnetite, and a colourless
interstitial substance with the refractive index and double refraction of nepheline.
J. 61 (587). Limburgite—Hand-specimen.—Very vesicular grey rock, porphyritic
in magnophyric corroded olivine grains. (See Plate IV, figs. 1 and 2.)
Teaxture.—P orphyritic hiatal, dopatic, megaphyric, with divergent radial fabric in
base (strahlenkérnig).
Composition.—T he phenocrysts consist of olivine and light green pyroxene, both
highly corroded. They are bordered with a rim of magnetite granules.
The base is holocrystalline, and consists of white prismatic pseudomorphs shaped
like large felspar laths, which are arranged in a divergent radial manner like the felspar
of ophitic diabase, and between these mineral groups lie intersertal masses of
titaniferous augite and magnetite in minute idiomorphic grains.
The divergent radial aggregates appear to be made up of minute idiomorphic
pyroxenes, quite colourless and non-pleochroic, with a slight interstitial amount of
nepheline. The pyroxene may be wollastonite, and the whole may be secondary after
an unstable anorthite or soda anorthite. The aggregates are at first sight suggestive of
the pinite pseudomorphs after labradorite im hebnerite porphyry, but the secondary
mineral is pyroxenic in habit and properties, not micaceous.
9. MAGNETITE BASALTS
These rocks are some of the most differentiated portions of the parent kenyte magma.
They are dark, heavy, more or less vesicular basalts, sometimes megaporphyritic,
sometimes aphanitic. The chief localities for these rocks are Cape Barne and Tent
Island.
Teature—They are usually muicroporphyritic hiatal, dopatic, hypo- or
hemi-crystalline vitrophyres.
Constituents.—The phenocrysts are usually extremely corroded, and consist of
felspar varying from oligoclase to basic labradorite, more rarely anorthoclase, corroded
olivines, augite varying from green egirine-augite to brown titaniferous augite,
magnetite, and idiomorphic apatite in stunted rods. The ground-mass consists mainly
of magnetite, though the high power may in places reveal the presence of brown glass
interstitially in a mass of dusty magnetite.
OF MOUNT EREBUS, ANTARCTICA ilar
J. 34 (1942). Magma Basalt, Tent Island.—Hand-specimen.—Black and vesicular.
Texture.—Porphyritic hiatal, dopatic, dominantly magniphyric, though a few
mediophyric phenocrysts occur. Fabric vitrophyric.
Constituents.—P henocrysts—zoned, corroded oligoclase and labradorite felspar
filled with apatite and glass inclusions, light greenish-brown girine-augite
(titaniferous), corroded olivine, sparing apatite rods. These phenocrysts are imbedded
in a black opaque mass which has by reflected light the steel-grey colour of magnetite,
and probably consists mainly of iron ore. (See Plate IV, fig. 5.)
J. 35 (1943), from Gap Moraine, Hut Point.—This contains corroded phenocrysts
of enstatite and olivine and no other phenocrystalline mineral. The base consists of
a brown to black mass, containing plagioclase microlites with feathery and pronged
ends (keraunoids and swallow-tailed microlites), imbedded in acryptocrystalline matrix
of black magnetite, brown, almost isotropic, pyroxene crystallites and brown pyroxenic
glass. In texture this rock is a porphyritic hiatal, sempatic basalt vitrophyre.
J. 17 (1926), Tent Island.—This is a red vesicular lava, and contains phenocrysts
of oligoclase-andesine and of greenish-brown augite. The former are corroded and
zoned, while the latter are idiomorphic in rods. Corroded olivines are also present.
These phenocrysts are imbedded in a reddish-brown, opaque, glassy base, consisting
largely of iron ores.
J. 22 (1981). Magnetite Basalt, Cape Barne.—Hand-specimen, dark compact bluish-
black rock, with small vesicles and slightly porphyritic in felspar.
Texture.—Porphyritic hiatal, vesicular, dopatic, mediophyric to microphyric, with
vitrophyric fabric in base.
Constituents.—The felspar phenocrysts consist of basic labradorite twinned on
Carlsbad, Baveno, and Manebach laws, as well as on the albite and pericline laws, several
types of twinning occurring together in each crystal. This felspar occurs sparingly
as megascopic, but plentifully as microscopic phenocrysts. Small augite rods forming
interpenetrating twins and corroded olivines also occur as microscopic phenocrysts.
The base is made up mainly of magnetite and dark isotropic glass.
The most remarkable thing about the magnetite basalts is the reversal of the order
of consolidation, the magnetite having been one of the last minerals to form.
GENERAL DISCUSSION ON DIFFERENTIATION
One of the most striking points about the Antarctic lavas examined is the highly
differentiated nature of the effusive products. The abundance of limburgites,
magnetite basalts, olivine nodules, sanidinite inclusions, etc., and the occurrence of
basalts without olivine, felspar basalts and olivine basalts in different interbedded
flows, show that differentiation was very complete, and that the eruptions tapped
now one, now another portion of the magma.
Specific gravity played a most important part in the differentiation. This is shown
by the occurrence of felspar basalts and augite andesites which R. A. Daly has
demonstrated to be formed by gravity differentiation (Jour. of Geol., July-August 1908).
The formation of the magnetite basalt is probably due to gravity; just as magnetite
has in one specimen, P.60,formed a secondary deposit round felspar phenocrysts, so have
phenocrysts of various minerals become enveloped in a clump of magnetite and dragged
down by the weight of the secondary deposit into the heavier magnetite layer. In this
way the phenocrysts of the magnetite basalts probably originated.
II Ss
118 PETROLOGY OF THE ALKALINE ROCKS
Prior has shown that these highly differentiated ferriferous basalts and limburgites
abound in many Antarctic islands. Such rocks occur also in Greenland and
Spitzbergen, and on basaltic volcanoes arising out of deep ocean.
It is not unlikely that the greater proximity of the Polar regions of the earth, and
of the magma caverns on the floor of the ocean, to the earth’s centre may stimulate
gravitative differentiation. So evenly are the various forces producing differentiation
balanced that a comparatively slight change in the conditions under which cooling
takes place may cause one force to greatly predominate over all others.
The same highly differentiated nature of Antarctic eruptive rocks is evidenced by the
alkaline, subalkaline, and basic lavas obtained by Borchgrevink at Cape Adare, and
described by David, Smeeth, and Schofield (cf. J. 1, and Proc. Roy. Soc. N.S.W., 1895).
There seems to be but little difference, if any, between the alkaline volcanic rocks
of Ross Island and those of the mainland.
The sequence of these lavas appears to have been the same as that which is so
characteristic of the Australian alkaline province—that is, from acid to basic.
The fact that the crater on the summit of Erebus is still erupting kenyte, while at
Cape Barne basalts are the latest effusive products, I do not take to indicate that these
lavas come from different magmas, but rather that the vent which gave the Cape
Barne lavas was supplied from a deeper source than the Erebus crater. The molten
magma has differentiated in the magma reservoir, and probably tongues of differentiated
rocks have been thrust into surrounding formations. Fissures may tap one or all of the
differentiation products, but the more elevated vents situated over the centre of the
magma chamber will tap the lavas in the order of their specific gravity, and will continue
to pour out each type of lava much longer than the subsidiary vents and fissures. Thus
if Cape Barne represents lavas poured from the fissure which has tapped sill-like
offshoots of the main reservoir, the whole sequence might be completed in this locality
while the summit of Erebus is still in the kenyte phase of eruption. The summit may
become extinct before emerging from this stage, the forces being insufficient in the
final stages of eruption to raise the subjacent basic lavas to the summit, so that these
may never reach the surface except by side fissures.
Yet the order of eruption would be from acid to basic wherever several lavas have
flowed from the same vent, and where flows from different vents have not intermingled
or overlapped. Such seems to have been the sequence of the lavas of Ross Island as
far as can be determined on present knowledge.
THE VOLCANIC ROCKS OF CAPE BIRD
The Cape Bird rocks of the Expedition’s collection were, according to Mr.
Priestley and Professor David, mostly water-worn and ice-carried specimens collected
at the foot of Cape Bird, which is a seaward projection of Mount Bird. None were
obtained in situ. *
Being derived from an independent focus of eruption, a special interest attaches
to them and to their comparison with the rocks of Mount Erebus.
The Cape Bird rocks are intimately related to those of Erebus, being alkaline in
facies. Their distinguishing feature is, however, in all varieties, the abundance of
brown basaltic hornblende and alteration products after this mineral.
The alteration products consist of magnetite, colourless augite, red hypersthene,
and apparently in some cases a red titaniferous hornblende, which may be a kaersuetite.
* Several of the specimens collected were in situ from the agglomerate formation at the landing-
place.—D. M., 1916.
OF MOUNT EREBUS, ANTARCTICA 119
In some cases magnetite is the sole alteration product recognisable in the pseudomorphs.
In other cases several of the above-mentioned minerals are present.
The formation of red secondary hypersthene by the molecular change of hornblende
has been ably described by Washington * in several papers dealing with the rocks of
Kula, in Syria.
The Cape Bird rocks consist of:
(1) Trachytes of a strongly alkaline facies, which generally contain pseudomorphs
after basaltic hornblende in greater or smaller amount.
(2) Kulaites or trachydoleritic rocks with the peculiar pseudomorphs after basaltic
hornblende which characterise kulaite.
(3) Subalkaline basalts and dolerites, some enstatite- bearing, some olivine-bearing.
The rocks of the kenyte series are absent in the Cape Bird rocks which have come
under my notice. It is, however, very probable that the complete Erebus series will
recur on Mount Bird, with this difference alone, that basalt hornblende and its
pseudomorphs will be present in all the rock species in varying proportions.
In most of the Cape Bird rocks examined the basalt hornblende has been altered
by the magma in such a manner that there can be little doubt that it is not a normal
differentiation product of the rocks in which it occurs. The subalkaline magma has
differentiated in the first place into an alkaline magma and a basic one, in the latter of
which hornblende was a normal consolidation product. The basic magma has then been
injected into the alkaline, and has been mixed with it in varying proportions whilst
differentiation of the alkaline magma was in progress, the hornblende undergoing partial
resorption and alteration. Then the differentiated alkaline lavas were extruded and
rapid cooling caused the final metamorphosis of the hornblendes.
P. 314 (622). Hand-specimen missing. Alkaline Trachyte, Cape Bird.—This is
a beautiful microcrystalline trachyte showing under the microscope a well-marked
flow structure.
Texture practically holocrystalline, dopatic, porphyritic serial in small felspar
phenocrysts, some of which are visible to the naked eye. There are also stray pheno-
crysts of corroded magnetite pseudomorphs after rod-shaped hornblende crystals.
These are minophyric.
The porphyritic felspar (magniphyric) consists of anorthoclase, as shown by the
fine multiple twinning and moirée accompanying a sanidine habit. The fine acicular
felspars of the base are probably also anorthoclase. The other minerals consist of
corroded grains of magnetite and wgirine-augite. A little isotropic felspathoid occurs
interstitially.
The rock, but for the hornblende pseudomorphs, is identical with some Mount Cis
trachytes.
P. 341 (653). This is a fluidal fine-grained hemicrystalline trachyphonolite
containing, in addition to the minerals of P. 314,nepheline and corroded olivine grains,
as well as a number of grains of camptonitic minerals appertaining to the inclusion
described in this rock by Mr. J. Allan Thomson.
J. 18 (1205). Altered Phyro-hornblende Trachyte, Cape Bird. (For Analyses see
Tables IVarAs ns 120 Table Va No. Viiwips 122). and Table” VE INox Vip p: 123;
Photo, Plate III, fig. 5). Megascopically this is a light grey rock dotted with black
rod-shaped phenocrysts. The structure is porphyritic hiatal, and slightly vesicular.
* Jour. of Geol., vol. viii, 1900; Am. Jour. of Sci., vol. xlvii, 1894; The Volcanoes of the Kula
Basin in Lydia,
120 PETROLOGY OF THE ALKALINE ROCKS
Microscopically, holocrystalline, megaporphyritic (hiatal), dosemic, magnophyric.
Fabric of ground-mass, trachytic. The phenocrysts have the outlines of hornblende,
but seem under the low power to consist of magnetite, but under the high power there
is seen to be present, in addition to the magnetite, a colourless augite (diopside), some
greenish augite (xegirine augite) and a reddish-brown mineral with hornblende cleavage
and straight extinction. The last mentioned has the pleochroism of kaersuetite, but
may be a hypersthene similar to that formed in similar pseudomorphs in kulaite.*
Larger remains of a highly pleochroic reddish-brown to greenish-brown (basaltic)
hornblende constitute the nuclei of several of the pseudomorphs, and may be original.
It is quite possible that this is a complex amphibole which has split up in some instances
into an aggregate of magnetite, diopside, «girite and a simpler titaniferous hornblende
(kaersuetite).
The grains are too minute to allow one to be confident of the determination.
That the black phenocrysts are psuedomorphs after hornblende is certain,
(See Plate ITI, fig. 5.)
TABLE IV. ANALYSES OF CAPE BIRD ROCKS
A B C D
J. 18
Phyrohornblende
Trachyte,
C. Bird
(Burrows &
Walkom)
No. 648
Kulaitic Basalt,
C. Bird
(Burrows and
Walkom)
Leucite Kulaite, Kulaite,
Kula, Kula,
Syria Syria
(Washington) (Washington)
Basalt,
Siebengebirge
(E. Kaiser)
52-54 48-26 49-90
1-44 0-88 0:93
19-41 22-67 19-89
2-90 3:22 2-55
5-31 4-56 4-78
0:23 0-11 trace
1:91 3-73 5-05
4-60 8-68 7-21
7:50 4-03 5-60
3-49 2:15 3:74
0-16 0-32 0-19
0-08 0-30 0-13
0-26 1-01 trace
0-20 trace —
100-03 99-92
The trachytic base consists of soda-sanidine, zegirine augite, arfvedsonite, and smaller
amounts of magnetite and hematite. The felspar and pyroxene are idiomorphic, the
arfvedsonite occurs in allotriomorphic grains, and the magnetite is mostly secondary
(opacite). Another slide made from a different specimen, P. 315 (626), is similar,
but the pseudomorphs contain larger nuclei of the original unaltered hornblende.
* Washington, op. cit. ante, p. 119.
+ Summation here includes chlorine and other constituents estimated by Washington but not
incorporated in this table.
OF MOUNT EREBUS, ANTARCTICA 121
Igneous Inclusions in Beacon Sandstone. Mr. Priestley left in my hands for
examination two microsections of Beacon sandstone with somewhat decomposed
inclusions of igneous rock. At first it was thought that the included lava fragments
were kenyte, to some of which they bore strong resemblance in texture. The minerals
were somewhat decomposed, so that identification was rendered difficult. A closer
examination of the slides revealed that the fragments bore a more strongly marked
resemblance to the kersantites described by Prior, and figured fig. 4, Plate IX, of his
report. These rocks, being intrusive into the basement rocks of Victoria Land, would
be more likely to occur in sandstone than would kenyte.
The trachyte with pseudomorphs after hornblende from Cape Bird is much more
basic than the normal trachytes tabulated in Table I(p. 98), and even more basic than the
kenytes. Yet it is a typically trachytic rock in hand-specimen and under the micro-
scope but for the abundant pseudohornblendes. It is these inclusions which account for
the basicity of the rock, raising the percentages of ferrous iron, magnesia, alumina,
and lime at the expense of silica. Comparison with analyses C and D, which with EH
are quoted from Washington’s Analyses of Igneous Rocks shows that this trachyte
is not a kulaite, for magnesia and lime are not as high and the alkahes higher than
should be the case in this group.
The kulaitic basalt (numbered 648) also varies in composition from typical kulaite
and is almost identical in composition with a basalt (Analysis, Table IV, E, p. 120) from
the Siebengebirge, which is also a noted alkaline province. The close chemical relation-
ship of the basic kenytes to the kulaitic basalts has already been referred to (ef.
Table II, p. 110), as has also the similarity in composition of this rock to the basic
autogenic inclusions in tephritic trachyte from Columbretes.
Calculated in the American classification the kulaitic basalt is in the subrang
Hessose, where its true affinities are quite obscured, and the trachyte J. 18 falls in the
subrang Hssexose, which is also an unnatural group for a rock of its mineralogical
features to fall into. (See Table VI, p. 123.)
THE KULAITE SERIES
J. 36 (1944). Auwlaite, Mount Bird.—The hand-specimen is a rough-fractured, grey,
andesitic-looking rock, megaphyric in larger felspars and smaller pyroxenes.
The texture is porphyritic hiatal, dopatic, magnophyric with a hypocrystalline
hyalopilitic fabric inclined to the diabasic structure.
The phanerocrystalline constituents consist of labradorite felspar, large phenocrysts
of bistre augite, smaller crystals of light-brownish augite, and occasional grains of
corroded olivine. There are also numerous dark patches whose outlines suggest that
they are pseudomorphs after hornblende. These are resolved by the high power into
a mixture of magnetite, colourless diopside, hypersthene needles, and felspar as described
by Washington.* (See Plate III, fig. 6.)
The ground-mass consists of acicular labradorite crystals, augite, enstatite, and
magnetite. The augite belongs to the same species as that of the phenocrysts. Many
of the finer constituents are simply fragmentary portions of broken-up pyroxene,
felspar phenocrysts, and of the pseudomorphs, and belong, strictly speaking, to the
first generation.
The second-generation minerals are, with the exception of the pseudohornblende,
identical with those of the first generation. In addition, rod-shaped enstatites are
present.
An isotropic glass, probably of leucitic composition, occurs interstitially.
* Jour. of Geol., April-May 1896.
PETROLOGY OF THE ALKALINE ROCKS
122
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124 PETROLOGY OF THE ALKALINE ROCKS
The rock is therefore a limburgitic basalt almost identical with kulaite.
The pseudomorphs of this rock, by the presence in them of felspar, strongly suggest
that the molecular alteration of the original hornblende was accompanied by replace-
ment of its molecules by molecules of the ground-mass.
P. 324 (648). Aulaite, Cape Bird.—This rock is similar to J. 36, but the alteration
of the hornblende has not progressed so far.
The texture of this rock is hypocrystalline and porphyritic, with phenocrysts,
partly idiomorphic and partly broken and corroded, scattered about as in vitrophyric
texture.
The phenocrysts consist of felspar belonging to the labradorite and andesine families,
faintly pleochroic augite (light green to light brown), unaltered barkevicitic hornblende
in idiomorphic crystals, and pseudomorphosed basalt hornblende in corroded crystals.
Apatite occurs as inclusions in all the minerals, and magnetite is very abundant as a
secondary constituent and both primary and secondary in the base.
The pseudomorphs consist of a granular mixture, chiefly magnetite, with colourless
augite and red hypersthene in some cases: in other cases the main alteration product
is a red hypersthene phenocryst with a rim of secondary magnetite and augite. It is
possible that this hypersthene is an original mineral, but both the association and the
occurrence in it at times of traces of hornblendic cleavage suggest that it is secondary.
Some of the felspar phenocrysts have tuning-fork ends.
The base consists of idiomorphic felspar laths, magnetite titaniferous augite, and
an isotropic glass. The magnetite of the base is largely secondary.
P. 325 (648). (For Analysis see Table LV, B, p. 120; and Table V, No. VIII, p. 122.)
This rock slice is similar to the foregoing. It is markedly porphyritic in faintly pleo-
chroic augite and basalt hornblende, undergoing the alteration described previously.
Some pseudomorphs consist mainly of a large crystal of red hypersthene with a mag-
netite-augite rim. Others consist mainly of an aggregate in which magnetite pre-
dominates over augite and hypersthene. The original phenocrysts of hornblende were
highly idiomorphic, but they have been largely broken and corroded in their meta-
morphosis. This idiomorphism is noticeable too with the felspar and augite phenocrysts,
some of which have been fragmented and corroded. (See Plate V, fig. 1.)
P. 317 (680). Kwlaite.—This rock is of a similar texture and constitution to
P. 325 but differs in the base, being much more evenly fine-grained in texture—
practically none of its constituents exceeding cryptocrystalline size and most of the
material is hyaline. The rock is sempatic and the phenocrysts are corroded and broken
as in the previous slide. The pseudomorphs are of exactly the same type, but the
proportion of unaltered hornblende is greater. The pleochroic augite is undergoing
chloritic decomposition, and magnetite in this slide occurs as a primary phenocrystalline
constituent as well as in the ground-mass, where it is developed both as a primary and
secondary mineral.
Felspar is a minor constituent so that this rock so if a somewhat more basic type
than the previous.
The four rocks just described are porphyritic hiatal with phaneric phenocrysts.
The texture is hypocrystalline inclining to vitrophyric in fabric. The phenocrysts of
hornblende in each show a remarkable variety of forms of alteration, depending, it would
seem, on the amount of iron in the original hornblende. The glassy base of each contains
a felspathoid, probably leucite.
These rocks he in the trachydolerite group and have affinities with the camptonites,
OF MOUNT EREBUS, ANTARCTICA 125
the limburgites, and the tephrites. The Kulaite of Kula, described by Washington,
agree with them in its characters, so that this name has been chosen for them. (For
Analysis see Table IV, p. 120.)
Closely allied to this group of rocks, but deficient in the hornblende and its pseudo-
morphs, are the tephritic and basanitic dolerites of the next group.
From the close similarity of the two groups it would seem that the kulaites are
derived by a mixture of a camptonitic with an alkaline doleritic magma.
THE CAPE BIRD DOLERITES
P. 334 (654). Olwine Basanite, Cape Bird.—This is a compact, dark porphyritic
rock, megaphyric in olivine. It has a porphyritic hiatal structure, and its base is very
fine-grained, hypocrystalline and hyalopilitic in fabric.
Olivine occurs as broken and corroded phenocrysts. Felspar occurs sparingly as
phenocrysts, also of broken and very corroded outlines. The felspar phenocrysts
consist of albite. In addition, we have rounded and corroded nepheline phenocrysts
and patchy masses of cancrinite after nepheline.
The base consists of pyroxene, magnetite, lath-shaped felspars, and glass.
The larger pyroxene crystals of the base are idiomorphic and consist of a brownish
to greenish pleochroic egirie-augite.
This rock is a very alkaline type of dolerite. The low felspar percentage puts the
rock in this basic division, but it has strong affinities with the tinguaites and phonolites.
P. 327 (649), Alkaline Dolerite.—This rock has close affinities with the kulaites
but is devoid of the basalt hornblende and its alteration product.
The structure is porphyritic, serial, sempatic, minophyric, with a tendency to a flow
arrangement. The texture is hypocrystalline with a variety of pilotaxitic fabric.
The main phenocrystalline constituents: augite, consisting of a faintly pleochroic
greenish to brownish pyroxene as in the kulaites ; zoned and corroded plagioclase, ranging
from oligoclase to acid labradorite ; and magnetite.
The base consists of brownish augite, magnetite, ilmenite, plagioclase, and a fels-
pathoid (probably leucite), and glass.
In both texture and composition this rock exhibits a great divergence from normal
dolerites and an approach to the basic kenytes and kulaites. Felspar and pyroxene
are about equal in amount.
P. 322 (642). Limburgitic Dolerite.—This rock is the most basic rock examined
for this locality. It is coarsely porphyritic—serial, in olivine ranging from magnophyric
size downward, and in enstatite ranging of minophyric size. These phenocrysts
are always broken and corroded, and sometimes invaded by the ground-mass, and clearly
belong to the intratelluric period. The first augite of the effusive period was only
faintly titaniferous and forms light-brownish idiomorphic crystals, but the finer augites
are deep in colour, being more highly titaniferous. Broken magnetite phenocrysts
occur, but, in addition, there is second generation of magnetite in the base. The felspar
percentage is very small and this mineral occurs only as fine microscopic needles of
labradorite. A small amount of interstitial glass occurs in the base. The order of
consolidation was: (1) magnetite, (2) olivine, (3) enstatite, (4) augite, (5) magnetite,
(6) felspar, (7) glass.
The most remarkable feature of the three basic rocks described is the dearth of
apatite, which is usually an abundant mineral in basic rocks. This feature clearly links
II ay
126 PETROLOGY OF ALKALINE ROCKS
them to the kenytes and other alkaline rocks in which phosphoric acid is, as a rule, very
deficient.
The Cape Bird rocks indicate that at this reservoir of magma there was an early
differentiation into a hornblende basalt magma and an alkaline kenytic magma, each
of which has again further differentiated and the final products obtained were mixtures
of the differentiates of these two magmas.
Original magma.
A, Hornblende basalt. B, Kenyte.
| | | | |
A,, Limburgite. A,, Olivine basalt. Aj, Kulaite. B,, Enstatite basalt. B,, Kenyte. P,,Trachydolerite. B,,Trachyte.
|
Basanite and Hornblende
Tephrite. Trachyte.
(A, + B,) (A, + B,)
The rocks of Cape Bird suggest that an examination of Mount Bird will reveal a
much more complete series of acid alkaline eruptives than has been poured from tbe
Erebus vent.
The abundance of basalt hornblende and pseudomorphs after this mineral in the
Cape Bird rocks, and their comparative absence in those of the Erebus series (except
at Cape Barne), in spite of the similarity in other respects of both series of rocks, is a
fact of some significance. It may, perhaps, be an indication that differentiation of the
Cape Bird magma commenced in much more deep-seated regions of the earth than
the Erebus magma, and the mixing of differentiation products, as already suggested,
might have taken place in the process of eruption.
The basaltic hornblende occurs, according to Prior, in certain basalts of Cape Bird
and in certain trachytes from Hut Point and Observation Hill. I also found pseudo-
morphs after hornblende in some Cape Barne basalts.
As may be gathered from the foregoing notes the nature of the pseudomorphs varies _
considerably. In some cases they consist w holly of magnetite, m others principally
of hypersthene ; in some of a mixture of grains of magnetite, hypersthene, and colourless
augite ; i some nuclei of the original basalt hornblende occur; in some a secondary
deep red to opaque pleochroic hornblende occurs with magnetite, augite, and felspar ;
this secondary hornblende has been referred to by Prior as a cossyrite-like hornblende,
but in my slides it has typically the characteristics of kaersuetite, though in some cases
it is very like cossyrite. The most extreme stage of alteration of hornblende seems to
be into a mosaic of magnetite augite and felspar, and where this occurs chemical inter-
action between the constituents “of the hornblende and of the matrix has probably
taken place.
Hornblende, more or less pseudomorphed, has also been described by Prior in rocks
from Mount Terror, so that this mineral seems to be widely distributed in all the rocks
except those of Krebus. That the volcanic rocks collected by Borchgrevink and by the
Scott expedition at Cape Adare are closely analogous to those of Ross Island is a fact
which is of great interest, and is further emphasised by the important collection of
erratics described by Woolnough.
EXPLANATION OF THE PLATES
(Photos by H. Gooch, University of Sydney)
PLATE I
Fieure 1.—Trachyte, Mount Cis, No. J. 1 (x 35, nicols uncrossed), showing trachytic
fabric near vesicle in left top quadrant, also a hexagonal pseudomorph after
nepheline to the right of the vesicle, and the pilotaxitic fabric of the rest of the
slide.
FicurE 2.—Trachyte, Mount Cis, No. J. 1 (x 45, nicols crossed), showing fabric.
Ficure 3.—Kaersuetite (?), Hgirine-Augite Trachyte, Observation Hill, No. J. 3( x 35,
nicols uncrossed). In the left top quadrant is seen a dark mass consisting of a
cluster of grains and rods of reddish-brown camptonitic hornblende.
Figure 4.—No. J. 3 (again) (x 45, nicols crossed). Near centre of slide is seen a
small idiomorphic brown hornblende crystal. Other grains and rods of the same
mineral are scattered throughout the slide.
Figure 5.—Anorthoclase Trachyte, Erratic, Ferrar Glacier, No. J. 54. (x 35, nicols
crossed.) This photo shows a group of anorthoclase phenocrysts (cumulophyre),
some of which are at extinction. The base shows along to top and left side of
the slide.
Figure 6.—Oligoclase Trachyte, Parasitic Cone of Erebus, No. J. 7 ( x 35, nicols crossed).
Shde showing bistre-coloured augite, olivine, mechanically zoned oligoclase and
anorthoclase, phenocrysts.
PLATE II
Ficure 1.—Acid Kenyte (holocrystalline), The Skuary, No. J. 40 (x 35, nicols crossed),
showing microline-microperthite phenocryst near extinction.
FicurE 2.—Same as Figure 1. Showing strahlenkérnig texture of base.
Ficure 3.—Vitrophyric Kenyte, The Skuary, No. J. 25 (x 35, nicols crossed), showing
part of very large rhomb-shaped anorthoclase phenocryst and a smaller micro-
perthitic felspar near extinction.
Ficure 4.—Vitrophyric Kenyte, Cape Barne, No. J. 48 ( x 35, nicols uncrossed), showing
an egirite phenocryst and crystallites in vitreous base.
FicurE 5.—Phonolitic Trachyte, Erratic, Cape Royds, No. J. 52 (x 35, nicols uncrossed),
showing vesicular structure and texture.
Ficurr 6.—Baked Alkali Trachyte, Tuff Cone, Ross Island, No. J. 50 (x 35, nicols
uncrossed), showing a large eegirine phenocryst.
PLATE III
Figure 1.—Leucite Kenyte, Mount Erebus (type specimen) (x 46, nicols uncrossed),
showing anorthoclase phenocrysts and structure of leucitic base. Note the rounded
leucite crystals.
Ficure 2.—Oligoclase Kenyte, Turk’s Head, No. J. 11 (x 35, nicols crossed), showing
twinned oligoclase phenocrysts.
127
128 PETROLOGY OF ALKALINE ROCKS
Ficure 3.—Same as Figure 2 (nicols uncrossed), showing leucitic base similar to
Erebus rock, Figure 1 ( x 46, nicols uncrossed).
Figure 4.—Trachydolerite Breccia, Parasitic Cone, Erebus, No. J. 12 (x 35, nicols
uncrossed), showing anorthoclase and plagioclase phenocrysts and the aschen-
structur.
Figure 5.—Phyro-pseudohornblende Trachyte, Cape Bird, No. J. 18 (x 35, nicols
uncrossed), showing huge magnetite phenocrysts replacing hornblende in trachyte
base.
Figure 6.—Kulaite, Cape Bird, No. J. 36 (x 35, nicols uncrossed), showing pseudo-
morph (largely magnetite and felspar) replacing hornblende.
PLATE IV
Ficure 1.—Limburgitic Basalt, Mount Erebus, No. J. 61 (x 454, nicols crossed), show-
ing olivine and pyroxene phenocrysts with kelyphitic borders, and a vesicle.
Figure 2.—Same slide showing divergent radial arrangement of the secondary laths
after felspar and nepheline.
Figure 3.—Leucite-Nosean Tephrite, Crater Hill, No. J. 31 (x 35, nicols slightly
crossed), showing rims of secondary felspathoid round vesicles.
Figure 4.—Same slide, nicols not crossed.
Ficure 5.—Magnetite Basalt, Tent Island, No. J. 34 (x 35, nicols uncrossed), slide
cracked ; note small felspar phenocrysts in magnetite base.
Fiaure 6.—Leucitophyr, loc. uncertain, No. J. 57 (x 35, nicols uncrossed). The
interiors of the large pseudoleucites have been ground away in making the slide.
PLATE V
Ficure 1.—Kulaite, Cape Bird, No. P. 325-(648) (x 35, nicols uncrossed), showing
magnetite pseudomorphs of magnetite after hornblende and also a hypersthene
pseudomorph with magnetite rim.
Fieure 2.—Olwine Basalt, Cape Barne, No. J. 49 (x 35, nicols uncrossed), showing
magnetite pseudomorph after hornblende.
Ficure 3.—Andesitic Basalt, Cape Barne, No. J. 2 (x 35, nicols crossed), showing
hyalopilitic vesicular ocellar texture.
PLATE I
Felspar
Bistre-
coloured
augite
Olivine
mee Gh Fic. 6
[To face p. 128
PLATE II
PLATE III
PLATE IV
V
\
4
PLATE
PART VIII
REPORT ON THE INCLUSIONS OF THE
VOLCANIC ROCKS OF THE ROSS
ARCHIPELAGO
(With Three Plates and Three Figures in the Text)
BY
J. ALLAN THOMSON, M.A., D.Sc., F.G.S.
CONTENTS
PAGE
I. OLIVINE, PYROXENE, AND GABBROID NODULES IN THE BASIC ROCKS 131
II. SANIDINITES AND MICROTINITES IN THE TRACHYTES AND KENYTES 134
SANIDINITES AND MICROTINITES IN THE TRACHYTE OF Mount Crs ; 3 134
SANIDINITES AND MICROTINITES IN THE KENYTES ; ‘ A ‘ < 136
OTHER SANIDINITES . A é : 3 : ‘ : ‘ ‘ 138
ORIGIN OF THE SANIDINITES AND MICROTINITES ‘ ; 5 ‘ 5 139
III. HORNBLENDIC INCLUSIONS IN THE TRACHYTES . i , : 5 140
ORIGIN OF THE HORNBLENDIC INCLUSIONS OF THE TRACHYTES . : 141
IV. ORBICULAR AUGITE-SYENITE: PROBABLY AN INCLUSION . 3 5 142
V. PLAGIOCLASE-PYROXENE INCLUSIONS IN THE TRACHYTE OF MOUNT
CIS : ‘ ; : 5 ‘ 5 ‘ 3 E : : ; 143
VI. QUARTZ-BEARING INCLUSIONS . : : : ‘ ‘ ‘ 5 ; 144
QuaARTZ-PYROXENE INCLUSIONS IN THE TRACHYTE OF Mount Cis ‘ : 144
QUARTZ-BEARING INCLUSIONS IN THE KENYTES . ‘ . 3 ; : 145
VII. CLASSIFICATION OF THE INCLUSIONS F j : 5 5 : ‘ 145
VIII. SUMMARY AND CONCLUSIONS . 5 : F ‘ ‘ : ‘ . 147
EXPLANATION OF THE PLATES . 5 5 5 ‘ : ‘ ' . 5 148
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Pera an (2
REPORT ON THE INCLUSIONS OF THE
VOLCANIC ROCKS OF THE ROSS
ARCHIPELAGO
(With Three Plates and Three Figures in the Text)
BY
J. ALLAN THOMSON, M.A., D.Sc., F.G.S.
Apart from the information that inclusions may give as to the sequence in age of
volcanic rocks and the constitution of the underlying terrane, their petrological
study may throw important light on petrogenesis. Lacroix, who has made a
speciality of these studies for many years, declared in 1893, after the examination
of over three thousand specimens: “‘ Cette richesse en matériaux nouveau me permet
de tirer quelques conclusions générales de mes observations, bien que j ale jugé nécessaire
d’étre fort prudent sur un sujet semblable, pour lequel les faits d’ observation ne seront
jamais trop nombreux.” *
The inclusions of a province petrographically so interesting as that of Ross Island
thus possess more than a local interest, and the geologists of the Shackleton Antarctic
Expedition are to be congratulated on the extent of their collections.
Although there is a general agreement as to the nomenclature of certain groups
of inclusions, their classification as a whole is still a subject of disagreement among
petrologists. The various groups will therefore be first described and their origin dis-
cussed before the attempt is made to show their place in a general classification.
Several types of inclusions have previously been collected by Ferrar and the officers
of the Scott Expedition, and described by Prior.+ Of these all but two were found
in the basalts and limburgites near Winter Quarters, and were of the nature of olivine
and gabbroid nodules. The two exceptions were enclosed in trachytes, the one being
a felspathic nodule or sanidinite, and the other consisting mainly of hornblende. All
the types described by Prior are included in the present collection with the exception
of the sanidinite from the trachyte of Cape Crozier.
I. OLIVINE, PYROXENE, AND GABBROID NODULES IN THE BASIC ROCKS
A large number of olivine, pyroxene, and gabbroid nodules were collected from the
basalts and limburgites of Hut Point. In some few cases the specimens were enclosed
in the volcanic rock, but more often they were loose, so that the exact nature of the
host could not be determined. Owing to the difficulty of preparing thin sections of
these loosely compacted rocks, but few slides were made, and the mineralogical com-
position was ascertained by crushing small fragments under oil on a glass slip and
examining the powder under the microscope. A more permanent preparation may be
* Lacroix, A., Les Enclaves des Roches volcaniques, Macon, 1893, p. 18.
} Ferrar, H. T., and Prior, G. T., National Antarctic Expedition, 1901-4; Natural History
vol. 1; Geology, Brit. Mus. Rep., London, 1907, pp. 11, 12, 14, 106-9, and 114.
II 131 ul
132 THE INCLUSIONS OF THE VOLCANIC ROCKS
made by mounting the powder in a solution of Canada balsam and xylol. With a little
practice very rapid examination may be made by this method, and in particular it is
more easy to distinguish olivine and pyroxene thus than ina thin section. Any mineral
present in small amount may, however, easily escape detection,
These nodules consist of associations of two or more of the following minerals:
olivine, a pale green augite (chrome-diopside), rhombic pyroxenes, brown hornblende,
biotite, a basic plagioclase, and a spinel. The associations are shown in the following
table :
‘al | RSET GN eal Ses ea | eal Nee FE GES |
2 oO ro) . a Ss
iad 8 a ES 2 s = Bae 2 = S Name of Corresponding
2 E 2 na cS) Ey £ as 5g 2 Fa Inclusion Plutonic Rock
Specimen 3 a AE a =I a Sie 3 = =
SS ies] A a a =
1209 | x | x Pe Alpe
1297 % . Dunite.
1193 x x x ]
1195 x x x Hornblende
1208 x x x Dunite.
1250 Me x x
1255 x x x Olivine
1252 x x x and Biotite Dunite.
ee = jen te = = —— _——
a ea al [ea ae] {
1210 x x x x Pyroxene (?) Biotite
1222 x x x x Nodules. Lherzolite.
1226 x x x
1841 x x .
1295 . < % . Lherzolite.
1230 x x x x J
1185 x x x x ear |))
1189 x x x
1900 x x x
1904 x x x Hornblende
1905 x x x Gabbro.
1906 x x x
1907 x x x
1908 x x x Gabbroid
1909 x x x x
1910 x x x x x x x r
1216 x
Nodules.
Gabbro.
KOK OK OX: Oe GX
The olivine is pale green in colour and very free from inclusions. The impregnation
with magnetite, described and figured by Prior* in some of his specimens, does not appear
to be represented in the present collection. A few of the nodules, however, are of a
reddish colour (“ rubifié””) owing to the separation of limonite from the olivine. The
* Loc. cit., p. 108.
OF THE ROSS ARCHIPELAGO 133
augite, on the other hand, is seldom free from ferruginous inclusions, both magnetite
and limonite are sometimes scattered irregularly throughout the mineral, and some-
times so disposed in small rods as to produce a schiller structure parallel to the vertical
axis, while rows of negative crystals occasionally run parallel to the base. Hypersthene
and enstatite show a similar schiller structure in a plane parallel to the vertical axis.
There appears to be no difference between the augite of the pyroxene and gabbroid
nodules, both giving extinction angles of over 40°. The felspar is a very basic variety
with extinction angles, on symmetrically cut albite lamellie, as high as 37° (labradorite-
bytownite).
As regards the quantitative relationships, in the olivine nodules olivine predominates
greatly over the other ferromagnesian minerals, which are generally present in quite
subordinate amount. In a few cases, however, augite occurs in such abundance that
the rocks may well be termed pyroxene nodules. ‘The rhombic pyroxenes are never pre-
sent in large quantity, a feature which Lacroix has noted as common when hornblende
is present.* In the gabbroid nodules the ratio between felspar and ferromagnesians
varies somewhat widely, as also does that between augite and hornblende. It will be
noticed that the spinel of the olivine nodules is chromite, whereas that of the gabbroid
types is pleonaste. Mr. W. N. Benson, of Sydney University, has pointed out to
me that the same law of association prevails in the inclusions of a large neck at
Dundass, near Sydney.
The structural relations call for little mention. Most often the rocks are quite
massive, but in one specimen (1909)+ there is a well-marked banding of felspathic and
ferromagnesian minerals. The olivine nodules are typically granular rocks, neither
olivine nor augite showing definite crystalline form (Fig. 1, Pl. I). Hornblende and
biotite, if present, are always the last elements of consolidation. In one specimen
(1193) there is a small veimlet of brown hornblende traversing the nodule, recalling
on a minute scale the association of hornblendites with the lherzolites of the Pyrenees. t
In the gabbroid nodules also the order of crystallisation is not well marked, although
olivine is clearly anterior to augite. There is no suggestion of ophitic relation of pyroxene
to felspar, but sometimes the augite appears to be intergrown with the felspar on its
edges. The brown hornblende surrounds the augite, and in one case is found chiefly
between the plagioclase and the olivine, probably in consequence of a magmatic resorp-
tion of the latter, but there is no radial orientation of the hornblende as in the well-known
teaction rims, nor is the hornblende found in parallel position on the augite.
Although hornblende is a frequent constituent of the above inclusions, it does not
appear as the main constituent of hornblende nodules, such as are often found in horn-
blende basalts. The collection includes, however, one large cleavage fragment of brown
hornblende measuring 3 by 1°5 cm. in its greatest diameters. It shows in places a
rounding and polishing that may be ascribed to magmatic corrosion.
As regards the origin of these inclusions, there is no doubt that they are closely
* Loc. cit., p. 486.
y The numbers attached to the specimens in this paper require some explanation. When the
paper was written, in September 1910, many rock specimens collected by the Expedition had not
been given registered numbers, and microscopic slides made from such specimens were labelled
T. 1 2, etc., when made to my order, P. 1, 2, ete., when made by Mr. Priestley, and E. 1, 2, etc.,
when belonging to the general collection of slides. I understand that the specimens of which
slides were prepared were deposited, with others, in the Museum of the Geological Department of
Sydney University, but that a duplicate collection was sent to Professor Lacroix at the Musée
d’Uistorie naturelle, Paris——J. A. T., January 1916.
{ Lacroix, A., “* Les roches basiques accompagnant les lherzolites et les ophites des Pyrénées,”
Compt. Rend. viii, Cong. Géol. Inter., Paris, 1900, p. 806.
134 THE INCLUSIONS OF THE VOLCANIC ROCKS
connected genetically with the rocks in which they occur. The origin of olivine nodules
has been the subject of a voluminous discussion into which there is no need to enter
here. The fact that the inclusions themselves form a differentiation series comparable
with that which would have been expected had the various basic volcanic rocks enclosing
them consolidated under plutonic conditions, suggests that they are actually frag-
ments from such a series which has arisen from the differentiation and consolidation
in depth of a portion of the primary basic magma.
I. SANIDINITES AND MICROTINITES IN THE TRACHYTES AND KENYTES
Sanidinite is the name given by Lacroix* to the coarse-grained miarolitic rocks con-
sisting predominatingly of sanidine or anorthoclase which are so often found as inclusions
of trachytes and certain kinds of phonolites. Similar rocks of more compact grain
and finer texture he has designated as “‘ micro-sanidinites.” Both types are represented
in the present collection, The analogous term “ microtinite”’ is used for similar in-
clusions consisting mainly of plagioclase felspar. t
Prior § has described a coarse-grained inclusion in the trachyte of Cape Crozier
which consists of an aggregate of stout felspar-prisms with some pleochroic (yellow
to grass-green) wgirine-augite and a little cossyrite-like hornblende ; the felspars are
partly oligoclase with symmetrical extinctions of about 8° and partly anorthoclase. This
rock appears to be a sanidinite, but differs considerably from those now to be described.
SANIDINITES AND MICROSANIDINITES IN THE TRACHYTE OF Mount Cis
By far the larger number of the felspathic inclusions have been found at Mount
Cis, a small parasitic cone 700 feet above sea-level on the foot of Erebus, about half-way
between Cape Royds and Cape Barne. The cone is composed of a dark grey highly
jointed rock determined by Dr. Jensen as a phonolitic trachyte.
The sanidinites vary in dimensions from fractions of an inch to several inches, and are
more or lessrounded in outline. Their immediate contact with the host is, however,
not smooth because of the injection of the ground-mass into the druses of the inclusion.
The rocks are seen in hand-specimens to be made up mainly of large platy felspar prisms,
more or less interlaced ;_ the spaces between the felspars are partly filled up with a brown
glass, partly with the dark grey vesicular ground-mass of the trachyte, but are seldom
completely filled, so that the whole mass has a most distinctly miarolitic aspect.
Numerous black iridescent crystals are seen in the druses and to a less extent within
the felspars themselves, and these prove on crushing under oil to consist of a very yellow
olivine. Less frequently small dark prisms (sometimes twisted) of egirine-augite
are found with the same mode of occurrence, and occasionally apatite and magnetite
are also noted. The length of the tabular felspars varies between a few millimetres
and 3°5 cm., their thickness in general being about one-fifth of their length.
Although on a general inspection the felspars appear to be of the same nature, micro-
scopical examination shows that in most specimens they consist of sanidine, but in a
few cases of anorthoclase. Cleavage fragments of the former show no twinning, while
a fine albite lamellation may be observed in the latter. This is in accord with their
properties in thin sections, the sanidine showing only Carlsbad twinning, the anortho-
* Les Enclaves, ete., p. 852.
j From microtine, a term proposed by Tschermak for the glassy plagioclases.
t Lacroix, A., “‘ Conclusions a tirer de l’étude des enclaves homceogénes pour la connaissance
dune province pétrographique—Santorin,”’ Compt. Rend. Acad. Sc., exl, 1905, p. 973.
§ Loc. cit., p. 114.
OF THE ROSS ARCHIPELAGO 135
clase on the other hand exhibiting the fine cross-hatching typical of the mineral as well
as sometimes only fine albite twinning (Fig. 2, Pl. I). Both varieties have refractive
indices less than those of Canada balsam and clove oil («= 1536) but when fragments
are immersed in monochlor-benzene (u—= 1°525) the indices of the sanidine are mostly
below that of the liquid, y alone being of about the same amount, while those of the
anorthoclase are mostly above 1°525, « alone being about the same. In habit the anortho-
clase appears to form stouter and shorter prisms. -
The following table gives the mineralogical composition observed by crushing
selected fragments of the rocks in suitable liquids:
enn nnn a EEEEEEEEEEEEEEEEEET?
SSMU 2: Sanidine Anorthoclase Olivine AXgirine-Augite Magnetite | Apatite Brow Glass
Specimen |
1728 x x x x x
1730 x x x x
1731 x x x x x
1734 x x x x
1735 x x x
1737 x x x
1744 x x > x x x
1747 x x x x x
1748 x x x x
1749 x x x x
1751 x
1756 x x x x
1757 x x x x x x
1760 x x x x x x
1761 x x x x
1767 x x x x x
1771 x x x x
1772 x x x x
1776 x x
1777 x x x
1821 x x x
1843 x x
1844 x x
1845 x x x
1846 x x
1976 x x x x x x
659 ] Erratic, x x
827 probably x x
1424| Mt. Cis. x x x x x x
So fragile are the rocks that the sections obtained do not give much further informa-
tion about the structure. The felspars when lying free in glass have perfect crystal
outlines(Fig. 2, Pl. I), but most often partially interfere with one another. Opaque
inclusions are somewhat abundant and are generally scattered irregularly through the
mineral, but occasionally lie in vertical planes in the crystal. The egirine-augite is a
strongly coloured yellow-green variety with a slight pleochroism. Cleavage flakes
give extinction angles of 37°-39°, whilst the largest extinction angle measured in section
(not quite parallel to 010) is 43°. In part, at least, the mineral has crystallised after
the felspar, on which it is moulded (Fig. 3, Pl. I). Fig. 4, Pl. I shows a crystal of
eegirine-augite lying ina druse of the rocks partly filled with ground-mass. The olivine,
though abundant in hand-specimen in well-formed crystals, is poorly represented in
section. It occurs frequently in the trachyte in the neighbourhood of the inclusions, and
136 THE INCLUSIONS OF THE VOLCANIC ROCKS
is there perfectly idiomorphic except for the inclusion of stout crystals of magnetite.
Apatite and magnetite are abundant in stout crystals, either in the druses or included
in any of the above minerals.
The interstitial glass and ground-mass possess interesting characters. Very often
there is a pale brown glass remarkably free from microlites, and in such cases there is
a gradual passage from the base of the inclusion into the ground-mass of the trachyte
by a gradual increase in the number of felspar microlites. In other cases the ground-mass
of the sanidinites is more coarsely crystalline than that of the host, from which it differs
also in the absence of flow structure (Fig. 5, Pl. 1).
The microsanidinites differ considerably from the sanidinites in outward appearance,
for they are typically compact, fine-grained rocks whose felspathic nature is not always
clearly evident at first sight. They are generally light-coloured, but sometimes contain
darker, coarser-grained, and miarolitic centres, whilst one specimen (1753) is altogether
dark grey and vesicular.
In section they prove to have a mineralogical composition similar to that of the
sanidinites, but they differ notably in structure. They are composed for the most part
of small quadrate prismatic felspars of which by far the majority are untwinned, or
show only Carlsbad twins and are to be referred to sanidine. The refractive indices are,
however, slightly higher than those of the sanidine of the sanidinites and are seldom
lower than that of monochlor-benzene (u=1'525) so that presumably they belong to
soda-sanidine. A few of the larger prisms show typical anorthoclase twinning, while
occasionally more elongate plagioclase (oligoclase-albite) is also found. Besides these
small quadrate felspars there are generally present much larger pseudoporphyritic
plates of anorthoclase, which partially envelop the sanidine. A yellow olivine is very
abundant in grains of similar size to those of the felspar mosaic, and is in places dis-
tinctly ophitic in structure. Agirine-augite also occurs, but is more idiomorphic.
Magnetite in small grains is widespread, whilst apatite is rare. Fig. 6, Pl. I, gives a
general view of the rock.
The dark miarolitic centres approach more nearly in structure to the coarse sani-
dinites, but are much darker in colour owing to the predominance of egirine-augite
in small prismatic crystals. Miss F. Cohen, of Sydney University, kindly undertook
a goniometrical examination of these, the results of which are appended to this paper.
The microsanidinites appear in most cases to pass insensibly into the ground-mass
of the host. The dark variety (1753) forms an exception, as it is sharply delimited
from the trachyte by a thin zone of large anorthoclase and olivine crystals.
A fragment of rock showing holocrystalline structure, specimen (1146), found as an
erratic at Cape Royds, may possibly be an inclusion from a trachyte. It is a mottled
yellowish grey and black rock of medium to fine grain, which bears some resemblance to
the sanidinites in one corner, where it is more felspathic and more coarsely crystalline.
It consists of anorthoclase prisms arranged in orthophyric fashion, with abundance
of interstitial «girine-augite and olivine largely replaced by magnetite, with a smaller
amount of barkevicitic hornblende in typically allotriomorphic forms. Apatite and
magnetite are richly present. The rock is thus a basic type of alkaline trachyte or
orthophyre. Whether it was brought to the surface as an inclusion or is a fragment
of a dyke remains uncertain.
SANIDINITES AND MICROTINITES IN THE KENYTES
Five felspathic inclusions have been obtained in the kenytes; with them will be
described two others found as erratics at Cape Royds on account of their similarity.
The mineralogical composition of these rocks is shown in the following table :
OF THE ROSS ARCHIPELAGO 137
Number of,
Specimen Locality and Host
Sanidine
Anorthoclase
Plagioclase
Magnetite
Hematite
Olivine
1971 | Kenyte, Cape Royds
x
x
1972 | Kenyte, Cape Royds
x
1793 | Kenyte, Inaccessible Island .
1847 | Erratic Kenyte, Cape Royds
1848 | Kenyte, Tent Island
1155 | Erratic, Cape Royds
1710 | Erratic, Cape Barne
The specimens from theCape Royds kenyte are small fragments, from which it is impos-
sible to infer the size of the whole inclusion. They are of moderate grain and are more
compact than the sanidinites of Mount Cis. In section they show large, somewhat
rounded phenocrysts of anorthoclase in a ground-mass of radially disposed microlites,
which from their straight extinction appear to be sanidine(Fig.1, Pl. Il). A pale brown
glass is very abundant, and from its occurrence in irregular patches and not in the
interstices of the rock structure it appears to result from remelting of part of the rock.
Irregular grains of magnetite are abundant within the phenocrysts and in the ground-mass.
A clear biotite occurs sparingly in large plates and also in clusters around the mag-
netite. On the exterior of the inclusion, the microlitic character disappears; large
and small rounded plates of anorthoclase with a little brown augite and small magnetite
grains form an irregular mosaic like that of a sandstone (Fig. 2, Pl. I).
The inclusion in the kenyte of Inaccessible Island is a spherical mass about 5 em. in
diameter. It is only slightly miarolitic, and consists of large platy twinned felspars
in a brownish felspathic matrix. In section the large felspars are seen to be andesine
with both Carlsbad and albite twins, and in opposition to those of the ground-mass
they are clear and glassy. The latter have a peculiar stippled appearance owing
to the separation of opaque matter (limonite) along both sets of cleavage planes.
They show only Carlsbad twins, and are to be referred to sanidine on account of
their refractive indices, but they occasionally contain clear kernels of anorthoclase.
For the most part they have stout columnar habit with an approach to orthophyric
arrangement, but there are smaller miarolitic areas partially filled by much more
slender microlites together with iron ores. Magnetite 1s abundant both as enclosures
in the felspars and in the interstices of the ground-mass. With it is associated a
very little biotite, and a greater amount of a yellowish green mineral of high
refractive index.
The inclusion in the erratic black kenyte found at Cape Roydsis a biotite microsani-
dinite. It contains large pseudoporphyritic plates of anorthoclase lying in a matrix
of small quadrate prisms of sanidine, anorthoclase, oligoclase, and glass. Well-shaped
large and small crystals of magnetite and more or less rounded plates of biotite are
abundant.
The inclusion in the kenyte of Tent Island is a large mass 8 x 5 x 6cm. The hand-
specimen shows large platy felspars with a miarolitic brownish red cement, in the midst
of which iridescent black crystals of olivine may be recognised. The large felspars
are zoned and twinned in a complex manner (Fig. 3, PI. 1) and prove to belong to oligo-
138 THE INCLUSIONS OF THE VOLCANIC ROCKS
clase and andesine. In their interstices another felspar may be detected in small lath-
shaped prisms. From its refractive indices between those of monochlor-benzene
(«= 1525) and clove oil («= 1536) it isdetermined as anorthoclase. It is accompanied
by large crystals of olivine and titaniferous augite enclosing apatite, small apparently
shapeless plates of hematite and biotite and much magnetite in large and small
rains,
‘ The two erratics (1155 and 1710) are presumed to be inclusions from the fact that
they bear a general resemblance to the sanidinites and differ from plutonic rocks in con-
taining a considerable amount of clear brown glass. They are further presumed to
be inclusions from the kenytes from the abundance of magnetite that they contain, and
in the case of (1710) from the presence of biotite. They have not been studied in section.
OTHER SANIDINITES
Microsanidinite in a Basic Rock from Hut Point (1238). The host is a reddish brown,
somewhat earthy basic rock, and the inclusion a small friable white rock. The powder
of the latter examined in oils shows that 1t is composed almost entirely of anorthoclase,
with zircon as the only other constituent in numerous stout prisms. The grain size and
general appearance recall the clearer microsanidinites of Mount Cis.
Erratic Sanidinite, Cape Royds (1357). This is a large angular rock which bears in
some places considerable superficial resemblance to the sanidinites, but is not miarolitic
like them, and is distinguished by the occurrence of large lustrous patches of black glass.
Microscopic study suggests that it is a sanidinite that has been partly remelted. The most
abundant mineral is a clear sanidine, partly in large plates with numerous enclosures of
glass and leucite, and partly as a fine mosaic. An augite of peculiar yellowish colour is
fairly abundant, also partly in large plates full of the same inclusions and partly as small
rounded grains clustered together. It has a colour more nearly yellow than green, is very
feebly pleochroic, gives extinction angles of 45°, and has strong dispersion of the bisec-
trices with an axial angle of nearly 90°. Perhaps the yellow colour is due to the reheating
which the rock appears to have undergone. Apatite is also an abundant constituent
in stout prisms with sharp pyramidal terminations where it lies in glass, a feature which
suggests a late crystallisation for the mineral. The glass, brown in thin section, occupies
relatively large areas of the rock. It has a refractive index slightly lower than that of
monochlor- benzene (= 1'525). Rosenbusch gives the indices of artificial syenite glass
as 1°520, and of monzonite glass as 1550.* Douglas ¢ obtained results still higher
for syenites and even more acidrocks. The refractive index of the brown glass in the
sanidinites of Mount Cis is also less than 1525, so that the glass of the rock under
description agrees well with what would be expected from the remelting of a
sanidinite.
Within the glass there are two minerals besides the apatite that have clearly separated
from the glass on cooling (Fig. 5, Pl. Il). One is magnetite in quadrate sections of large
and small octahedra, in whose immediate vicinity the glass is decolorised. The abund-
ance of the magnetite is probably connected with the melting of olivine or biotite,
although why the former did not recrystallise is difficult to understand. The other
mineral is still more abundant in small sharp colourless perfectly isotropic crystals with
low relief. They have sometimes quadrate forms, occasionally truncated at the corners,
and sometimes hexagonal forms. A few cleavage traces are observed on both forms,
* Mikr. Phys., i, ti, Tabelle I, 1905.
+ Douglas, J. A., “* Changes of Physical Constants in Minerals and Igneous Rocks, on the
Passage from the Crystalline to the Glassy State,” Q.J.G.S., xiii, 1907, p. 153.
OF THE ROSS ARCHIPELAGO 135
and in each case run parallel to the dominant faces, 7.e., the cleavage net is respectively
rectangular or triangular, and therefore probably dodecahedral. The refractive index,
superior to that of xylol (u=1°494), excludes analcite and sodalite, so that the mineral
must be leucite. This too is what would be expected in the melt of a rock consisting
largely of sanidine.
There is no clue as to the rock in which this inclusion was remelted, but the above
description renders it probable that the sanidinite originated in a trachyte.
ORIGIN OF THE SANIDINITES AND MICROTINITES
The origin of sanidinites in trachytes appears at first sight very simple. They consist
in general of the same minerals as the phenocrysts of the rock, and appear to have
arisen by a simple aggregation of these minerals; another plausible view is that
they represent a complete crystallisation in depth of a portion of the trachytic magma,
perhaps as a wall to the magma basin, and have been broken off and included in the
still unconsolidated magma on eruption. Lacroix, in his earlier work,* considered the
latter the more probable mode of origin; but subsequently he has shown that sani-
dinites may arise in many different ways. For instance, trachytes appear to have the
power of converting inclusions of such rocks as older trachytes, gneisses and granulites
into sanidinites f and this may have happened in many cases where the intermediate
steps can be no longer traced. A still more curious origin is put forward for some
sanidinites in the basic leucitic tuffs of Somma.{ Besides the sanidinites the tufts
contain blocks of metamorphosed limestones which have locally the constitution of
sanidinites, and the isolated sanidinites are assumed to be fragments broken off from
the limestone blocks. The origin of the sanidine in the cavities of the limestone is
ascribed to contact alteration accompanied by an exudation of soda into the limestone
under pneumatolytic conditions. It is obvious, therefore, that the explanation of the
origin of the sanidine in any rock must be carefully scrutinised.
The peculiar feature of the Mount Cis sanidinites is the predominance of olivine
over wgirine-augite, in opposition to its rarity in the trachyte. A further mineralogical
difference between the two rocks is the absence of the alkaline amphiboles in the former
and their presence in the latter. Chemically expressed, the sanidinites are richer in iron
and magnesia than the trachytes and poorer in hime. They cannot therefore be regarded
as simply a deep-seated crystallisation of a part of the trachyte magma, unless some
differentiation is admitted. One specimen might suggest that they are simply aggrega-
tions of phenocrysts (Fig. 4, Pl. II), but phenocrysts of sanidine are not at all common
in the trachytes, and the specimen might be interpreted equally well as a sanidinite
that had been partly broken up by movement in the trachyte.§
The microsanidinites present the same mineralogical differences from the trachytes
as the sanidinites. From their orthophyric structure they point more clearly to deep-
seated crystallisation, with a slight amount of differentiation. The development of
a thin zone of coarse crystals around one of them (1753) perhaps gives the clue to the
origin of the sanidinites. The latter may have been originally inclusions of orthophyric
trachyte which the trachyte magma has by the power of its mineralising vapours trans-
* Les Enclaves, etec., pp. 358 et seq.
+ Lacroix, A., “Sur deux nouveaux groupes d’enclaves des roches éruptives,” Bull. Soc. fr.
Min., xxiv, 1901, pp. 488-504.
{ Loc. cit.
§ This specimen was sent away to the International Geological Congress at Stockholm, so that
the writer has not heen able to re-examine it.
II U2
140 THE INCLUSIONS OF THE VOLCANIC ROCKS
formed into the coarse-grained rocks we now see. The negative evidence against this
view is, however, stronger than the positive, and it is perhaps best, in the present state
of our knowledge, to consider them also as fragments of deep-seated rocks of close genetic
connection with the trachyte magma.
The materials for the study of the felspathic inclusions of the kenytes is, unfor-
tunately, very meagre, but it is of interest to find that both sanidinites and microtinites
can originate in kenytic magmas. The most noticeable mineralogical difference from
the kenytes lies in the presence of biotite, a mineral not recorded at all from the volcanic
rocks. It is well known that a dry melt of orthoclase and biotite in certain pro-
portions will recrystallise under slow cooling as a mixture of olivine and leucite. The
two last minerals are found occasionally as phenocrysts in the kenytes, so that it
appears that the biotite, and therefore the rocks containing it, crystallised under
different conditions of pressure from those which prevailed during the formation of
the phenocrysts of the kenyte. The inclusions cannot therefore be simple aggrega-
tions of phenocrysts.
There is a close correspondence between the natures of the hosts and of the inclusions.
Sanidinites are found in the acid kenyte of Cape Royds which contain anorthoclase as
phenocrysts, while microtinites are found in the basic kenytes of the Delbridge Islands,
which contain phenocrysts of oligoclase. The augite of both types of inclusion is titani-
ferous and not egirine-augite as in the sanidinites of the trachytes. From this
correspondence it may be safely inferred that the inclusions originated from the same
magmas as the rocks enclosing them. Further inquiry as to whether they are fragments
of already consolidated portions of the magmas or foreign fragments that have been
reconstituted by the influence of the magmas cannot be profitably followed on the
evidence available. The microlitic structure of the ground-mass points to the former
view.
Ill. HORNBLENDIC INCLUSIONS IN THE TRACHYTES
Inclusion in the Trachyte of Observation Hill. Prior has already noticed the rounded
brownish enclosures in the trachyte of Observation Hill: “ Under the microscope they
consist of a dense mesh of interlacing prisms of basaltic hornblende, similar to that in
the trachyte, with magnetite grains and only a little interstitial felspar. The hornblende
in these enclosures and in the trachytes has the characters of barkevicite.” *
This type is represented by only one specimen in the present collection. It agrees
in general characters with those described by Prior, but 1t may be noted that besides
the fine iterlacing prisms of hornblende there are a few larger and proportionately
stouter prisms which stand to the former as phenocrysts to ground-mass, and thus give
the rock a lamprophyric character. The untwinned felspar has refractive indices
slightly lower than that of Canada Balsam, and probably belongs to anorthoclase.
Inclusion in the Trachyte of Cape Bird. A specimen of a dark green phonolitic
trachyte from the beach pebbles of Cape Bird proves to be rich in small hornblendic inclu-
sions. They are more coarsely crystalline than the Observation Hill type, and are
markedly vesicular with minute crystals of analcite in the vesicles. Under the microscope
hornblende, augite, olivine, felspar, magnetite, apatite, calcite, and analcite may be recog-
nised. The structure is distinctly porphyritic ; colourless olivine in prismatic forms with
acute pyramidal terminations and pale lilac titaniferous augite in long prisms with
obtuse pyramids terminated by the basal plane appear to have formed the earliest pheno-
crysts, since hornblende is occasionally moulded on both minerals. A considerable
amount of magmatic resorption has affected the augite in cases where it is enclosed with
* Loc. cit., p. 118 and Fig. 66.
OF THE ROSS ARCHIPELAGO 141
rounded forms within the hornblende along with grains of magnetite. Fig. 1a shows the
normal course of the resorption and Fig. 1b an unusual case where it has taken place
on one side of the augite only, with the development of the hornblende in parallel
position. The hornblende is a common brown variety with pleochroism from brown
to yellow-brown, and is perfectly euhedral where it does not impinge on olivine or
augite, with the faces M (110), B (010), A (100), and dome terminations. Felspar
occasionally forms large lath-shaped crystals comparable in size to the above-named
Fic. la Fic. 1b
minerals, but cannot be considered a phenocryst, since it includes abundantly the fine
hornblende needles of the ground-mass. It shows simple albite twins with low extinction
angles, but too few opportunities of measurement present themselves to determine the
maximum, nor can the refringence be compared with that of balsam since the mineral is
always surrounded by analcite. The latter occupies large areas of the ground-mass, of
which the chief constituent is hornblende in small prisms crossing one another in all
directions. The amygdules are generally completely filled with analcite and calcite, the
former being the earlier mineral in sharp crystals (Fig. 6, Pl. I).
On the assumption that a calcic felspar has been replaced by analcite and calcite,
the rocks agree in all respects with olive camptonites.
ORIGIN OF THE HORNBLENDIC INCLUSIONS OF THE TRACHYTES
Lacroix has found that inclusions more basic than their host, although not so
common as inclusions of sanidinites, have nevertheless a wide distribution in trachytes,
especially in those rich in ferromagnesian minerals. They are for the most part of the
nature of porphyrites. In phonolites the analogous inclusions are generally camptonites,
rocks which, he points out, frequently accompany nepheline syenites, the plutonic
representatives of phonolites. He considers them, nevertheless, as basic segregations
from the phonolitic magma.*
While the Observation Hill inclusions might easily be considered as segregations,
since the same hornblende is so abundant in the trachyte, the Cape Bird camptonites
cannot be so regarded. The alteration they have undergone could scarcely have taken
place had they never existed but within the trachyte, since the latter is a_ relatively
fresh rock. It is simpler to conceive of them as fragments of true camptonites which
were completely consolidated and partly altered before they were enclosed in the
trachyte magma.
The fact that the basic inclusions of the Ross Island trachytes are camptonites and
not porphyrites is a further confirmation of the phonolitic affinities of these trachytes.
* Les Enclaves, ete., p. 416.
142 THE INCLUSIONS OF THE VOLCANIC ROCKS
IV. ORBICULAR AUGITE-SYENITE : PROBABLY AN INCLUSION
An Erratic from half-way between Cape Royds and Cape Barne, near Mount Cis.
The reasons for assuming that this rock is an inclusion of some volcanic rock are, first,
the alkaline affinities of the rock, and secondly, the abundance in it of a brown glass
similar to that described in so many of the above inclusions.
The hand-specimens (1974 and E33) are small angular fragments which show for
the most part a banded character, and only in one case a complete spherule. The
accompanying sketch (Fig. 2) of a polished surface, kindly drawn by Mr. W. N. Benson,
of Sydney University, gives a clear
idea of the macrostructure. The
dark bands and the centre of the
spherule owe their colour in part to an
augite, but more particularly to mag-
netite. The clear bands consist pre-
dominantly of felspar.
The augite is a brownish green
variety without marked pleochroism.
The dispersion of the bisectrices is so
strong that the mineral often does not
completely extinguish, but the extine-
tion angle Z (Ac is approximately 32°.
The axial angle is nearly 90°. From
the brownish colour and strong dis-
persion the mineral must be classed
with the titaniferous augites. It occurs
in anhedral elongate plates, which are
relatively large when they are found in
the centres of the spherules or between
Fic. 2 the dark bands, and in these cases are
set more or less radially. Occasionally
in the small clear bands it occurs in small rounded grains. In the dark bands it is
generally in much smaller crystals and elongated tangentially to the spherules. In
both cases it is rich in magnetite inclusions, arranged perpendicularly to the elonga-
tion, and occasionally encloses a brown glass.
The felspars show a great diversity of twinning; untwinned forms are abundant,
and so are forms with cross-hatchings of various degrees of sharpness from mere
moiré extinctions to twinning scarcely to be distinguished from microcline twinning ;
simple albite twinning with low extinction angles is comparatively rare. The
refractive indices of all these lies not far from that of Canada balsam. More exact
determinations in liquids of known indices show that none lie below 1:525, and most
lie between 1536 and 1540. A plagioclase in cleavage flakes shows one index below
1540 and one above; it therefore belongs to oligoclase; the rest of the felspar
appears to belong to anorthoclase with unusually high refractive indices, and probably
therefore rich in the anorthite molecule. Like the augite, the felspars vary in size
according to their position. Within or near the dark bands they form a fine-grained
polygonal mosaic; between the dark bands and in the centre of the spherules they
have a tendency to an elongate radial habit. They enclose small magnetite grains
and an abundance of fine colourless needles, too small for exact determination. Some
larger prisms with cross-fractures are certainly apatite, but the majority of the
needles are probably sillimanite.
OF THE ROSS ARCHIPELAGO 143
A brown glass is found somewhat abundantly in certain bands, both as inclusions
in the felspar and augite and as an interstitial base. In the latter case it encloses
well-shaped octahedra of magnetite and is crowded with arborescent crystallites,
In addition there is occasionally a clear mineral of moderate refringence and low bire-
fringence, which is biaxial with a moderate axial angle and optically negative. In
crushed fragments of the rock this mineral is seen to be well crystallised and
appears to be orthorhombic, with pinacoids, basal plane, and dome faces. It has not
been definitely determined.
If the presence of glass be neglected, the rock has the mineralogical composition
of an augite syenite (of the soda syenite family) and may be termed an orbicular augite
syenite. The glass included in the minerals might have arisen by remelting, and in one
of the specimens has very much the appearance of having arisen in this way; that
occurring interstitially, however, appears to be the result of a normal stoppage of
crystallisation due to sudden cooling. The alkaline affinities of the rock ally it to the
volcanic series of Ross Island, and the hypothesis is put forward that it was torn from
its place before consolidation was complete, and brought to the surface either in a lava
or a volcanic breccia.
V. PLAGIOCLASE-PYROXENE INCLUSIONS IN THE TRACHYTE
OF MOUNT CIS
Among the fine-grained compact inclusions from Mount Cis there are four charac-
terised by a mottled greenish grey appearance. These prove on microscopic
examination to consist of a basic plagioclase and pyroxene with subordinate magnetite
and sphene, and in one case calcite. The plagioclase generally occurs in large tabular
plates with both Carlsbad and albite twins, and is referable from extinction angles
to labradorite. The pyroxene in three of the specimens (T 7, P 33, and 1969) is a pale
green monoclinic variety with oblique extinctions up to 44° and a high axial angle.
In the other (E 35) it is an almost colourless variety with straight extinctions and is
optically negative and therefore referable to bronzite. The pyroxenes generally have
an ophitic relation to the felspars, but in parts of the rocks the structural relations
have been more or less broken down, and the pyroxene is found as small"grains inter-
mixed with and included in small felspar plates (Fig. 1, Pl. Il).* In places a
brown glass appears, either as inclusions in the felspars, or as an interstitial matrix in
which small euhedral felspars are embedded (Fig. 2, Pl. III). In one rock (EH 35) the
felspar is accompanied by a colourless, more strongly refringent mineral which appears
to be wollastonite. In the same rock there is a vesicular glassy selvage against the
trachyte, in which large plates of anorthoclase are developed.
These inclusions must be interpreted as fragments of dolerites that have been par-
tially melted and recrystallised, with a slight admixture of trachytic material on the
edges. The dolerites appear to have no alkaline affinities, and can scarcely be derived
from the trachytic magma or its allies.| They are probably fragments of sills intrusive
into the Beacon sandstones such as occur on the mainland.
* From the resemblance of these apparently granulitic parts of the rock to some of the pyroxene
granulites that are found as erratics at Cape Royds, the writer was at first inclined to regard these
rocks as inclusions of granulites, and this view was published in the preliminary account of the
Geology by Professor David and Mr. Priestley, Compt. Rend. Congr. Geol. Inter. Stockholm, 1910.
The absence of the characteristic clove-brown wedges of sphene and the ophitic character of the
least disturbed parts of the rock are against this view.
+ They present little resemblance to the gabbroid nodules described above.
144 THE INCLUSIONS OF THE VOLCANIC ROCKS
VI. QUARTZ-BEARING INCLUSIONS
QUARTZ-PYROXENE INCLUSIONS IN THE TRACHYTE OF Mount Cis
These are small, rounded, compact, greyish white inclusions, at first sight similar
to some of the microsanidinites, but distinguished from them on close examination
by the presence of small grains of quartz. With them must be included a number of
very vesicular brown inclusions, since in some cases the latter contain a kernel of the
former.
Under the microscope the first type 1s seen to consist mainly of numerous large grains
of quartz separated by smaller grains of the same mineral and of a pale yellow-green
augite (Fig, 3, Pl. III). Occasionally the pyroxene has a sieve-like or poikilitic develop-
ment, enclosing grains of the other minerals indifferently. In some specimens a turbid
plagioclase (labradorite) also occurs in large grains, but never in amount equal to the
quartz. Wollastonite can be definitely identified in one section (E 14) in long prisms
enclosing small granules of augite, and is suspected in others. Magnetite appears
in most specimens in irregular blotches and small grains, and sphene is found in a few
in large rounded forms. Calcite appears in only two specimens. In all a greater or less
amount of a clear brown glass is present.
Sometimes the structure of the inclusion remains unaltered right to its contact with the
host, but where the quartz grains abut against the trachytic ground-mass there is an
ingrowth of a green augite, near wgirine in its properties, from the host.
This phenomenon is still better exemplified in cases where sporadic xenocrysts of
quartz have swum in the trachytic magma (Fig. 4, Pl. III). At other times a
different form of contact is observed; the inclusion becomes slaggy and vesicular
towards the edge, and in section is predominantly glassy with an occasional development
of large anorthoclase crystals besides the sharp augite prisms, some partially molten
quartz grains still remaining.
There is little doubt that the wholly slaggy and vesicular inclusions represented
melted rocks of the same nature as those which gave rise to the quartz-pyroxene type.
The rocks are excessively fragile, and no satisfactory sections were obtained, but
examination of crushed fragments in oil shows that they consist chiefly of a clear brown
glass with a variable amount of quartz, augite, magnetite, and numerous prismatic
crystals of a mineral which could not be definitely determined. It has refractive indices
superior to those of wollastonite, which it resembles in its straight extinction and
moderate birefringence. It is biaxial with a low optic axial angle, is negative and has
positive elongation of the prisms.
One specimen (E 17, T 5) merits separate description. It has a vesicular contact
zone with the host of about 1°5 cm. in width. The kernel (4 cm. in diameter) has
a thin white shell, but is much darker in the centre than is usual in this type of rock
(Fig. 5, Pl. III). The contact zone is similar in general characters to the above described
rocks, containing the quartz, augite, and the undetermined mineral all lying in a brown
glass. The outer part of the kernel resembles the more compact inclusions. The dark
colour of the centre is due to the prevalence of finely distributed magnetite dust. Large
clear quartz grains are still present, but they are fewer and farther apart, and there
are in addition a few grains of an intermediate plagioclase. These minerals are all
enclosed in large interlocking plates of a mineral which resembles cordierite both in
habit and in the abundance of magnetite inclusions. It is biaxial with a moderate
axial angle, and optically negative and may thus be cordierite or a felspar of the ortho-
clase-anorthoclase series. No twinning was observed. On the margin between the
dark centre and the clearer exterior there are numerous granules of strongly pleochroic
hypersthene, often developed at the edge of large quartz grains.
OF THE ROSS ARCHIPELAGO 145
All these inclusions, from the abundance of quartz they contain where not exten-
sively melted, may be safely referred to fragments of impure sandstone. The presence of
augite, wollastonite, and calcite shows that there must have been some lime present,
possibly as a calcareous cement.
QUARTZ-BEARING INCLUSIONS IN THE KENYTES
Two specimens only of this nature have been collected. The one was included
in the kenyte of Cape Royds, the other in that of Sentinel Hill. The former is a fine-
grained brownish grey banded rock, with large rounded cavities. In section it is seen
to consist of quartz in small angular grains, with lesser amounts of felspar, augite, and
magnetite. The brownish colour is due partly to a glassy base, and partly to limonite
staining. The felspar occurs in short rectangular forms giving symmetrical extinction
on albite lamelle of 33°, and is therefore labradorite, although more acid species may also
be present. The augite, on the other hand, is found in highly irregular embayed forms
and treely includes quartz.
The other inclusion (EH 20) is a slightly reddish streaky rock with a sintery appear-
ance which microscopic examination shows to be due to an abundance of glass. The
clear streaks are composed mainly of small rounded quartz grains lying each isolated
in the glass. Occasionally, however, they are accompanied by thin needles of a colour-
less mineral, which from its straight extinction, positive elongation, and moderate
birefringence appears to be silliimanite. Where there is the richest development of
these needles there are also some small clear hexagonal overlapping plates of tridymite.
There are a few larger prisms and rounded plates of another clear mineral, with refrin-
gence and birefringence much superior to those of quartz. It is uniaxial or almost so,
and optically positive.
The more turbid streaks are almost opaque in section, and appear to consist
largely of glass with smaller amounts of the above-named minerals, together with
much fine opaque dust. In a few patches they are excessively rich in minute needles,
probably of silimanite. Magnetite and hematite are abundant in both parts of
the rock.
This rock, like the last, is clearly an altered sandstone.
VII. CLASSIFICATION OF THE INCLUSIONS
From the above descriptions and discussions it will be obvious that the inclusions
can be sharply separated into two categories, the one including all those rocks which
are genetically connected with the volcanic hosts, the other comprising those that have
no such connection and have been broken off from the sedimentary or older igneous
rocks through which the volcanic lavas ascended. This underlying distinction has been
made the basis of all the classifications that have been proposed. As early as 1884
Sauer proposed the terms “‘ endogene” and “exogene” for the two classes, and
his terms are still applied by some German writers.* Lacroix in 1893 rejected them
for the terms “homceogéne” (from @addos, analogous, and yervao, I beget) and
“énallogéne” (from éuoos, different, and yevae), since the genetic relationship is
not necessarily one of direct parentage, such as is implied in the term endogene.f
Sollas in 1894 proposed the terms “ xenocryst” and “ xenolith” for foreign
* Sauer, Erlaut. Preuss. Geol. Landsanst, Sect. Wiesenthal, 1884, p. 70.
{ Les Enclaves, ete., p. 7.
146 THE INCLUSIONS OF THE VOLCANIC ROCKS
crystals and rocks respectively without discussing the genetic origin, and these terms
have come into general use in English.* Harker in 1900 proposed to replace Lacroix’s
terms by the terms “ cognate xenoliths” and “ accidental xenoliths” respectively,
on the ground that Lacroix relied on analogies of composition between inclusion and
host and not upon analogies of origin. Holland the same year suggested the term
“autolith” in antithesis to ‘‘xenolith,” rejecting Lacroix’s term owing to a mistranslation
of “homoeogéne” by “homogeneous.” t Inthe subsequent year Lacroix pointed out that
Harker’s criticism was based on a misunderstanding :
“Le principe énoncé par M. Harker est précisément celui qui m’a guidé dans
létablissement des deux groupes d’enclaves en question et dans leur nomenclature ? ’’§
Harker in 1909 repeated his objections in a modified form,|| but, in the writer’s
opinion, has not succeeded in demonstrating the unsuitability of Lacroix’s terms
or the superiority of his own. Lacroix’s classification is therefore adopted in
this paper.
Lacroix has further subdivided his group of homceogenous § inclusions into the
following groups: **
Allomorphe : ‘ : : : . homologue.
antilogue.
Plésiomorphe . : : : é . homologue.
antilogue.
Polygéne . - : é : : - exopolygene.
endopolygéne.
Pneumatogéne.
The allomorphous inclusions are those torn from masses already consolidated in
depth. The plesiomorphous are segregations formed in the magma that have not
had a separate existence as geological units. For these Holland’s term of autolith
seems appropriate. Either of these two types may be homologous, 7.e. formed by the
integral consolidation of the mean type of the enclosing magma, or antilogous, 7.e.
formed by basic differentiation or original heterogeneity. The polygenous types are
those which have arisen by the action of the magma on included fragments of other
rocks, the endopolygenous resulting from a complete melting of the inclusion and the
crystallisation of the endometamorphosed portion of the magma, the exomorphous
from the transformation of the inclusion under the influence of emanations coming
from the magma. The latter type must therefore grade off into enallogenous inclusions.
Finally the pneumatogenous types arise in the way described above for the sanidinites
of Somma (vide ante).
It is obvious that this classification is ideal and can only be applied in cases where
* Sollas, W. J., “ On the Volcanic District of Carlingford and Slieve Gallion,” Part I; “ On
the Relations of the Granite to the Gabbro at Barnanave, Carlingford”; Trans. Roy. Irish Acad.,
xxx, 1904, p. 493.
+ Harker, A., “Igneous Rock Series and Mixed Igneous Rocks,” Journ. of Geol., viii, 1900,
p- 309.
t Holland, T. H., “The Charnockite Series; a Group of Archzean Hypersthene Rocks in
Peninsular India,” Mem. Geol. Surv. India, xxviii, Part II, 1900, p. 217.
§ Lacroix, A., “Sur deux nouveaux groupes d’enclaves des roches éruptives,” Bull. Soc. fr.
Min., xxiv, 1902, pp. 488-9.
|| The Natural History of Igneous Rocks, pp. 346, 347, 1909.
4] Dr. Craigie, one of the collaborators on Murray’s Oxford Dictionary, in conversation with
the writer in 1907 suggested ‘“‘ homceogenous ”’ as the correct English translation of ““ homceogéne.”
** La montagne Pelée et ses éruptions, Paris, 1904. Also Bull. Soc. fr. Min., xxiv, 1901,
pp. 488-504.
OF THE ROSS ARCHIPELAGO 147
the origin of the inclusion is beyond doubt. The following application to the present
collection * is therefore put forward tentatively:
Homa@ocenous IncLusions
Allomorphous, homologous . ° - - Olivine nodules in limburgites.
Gabbroid nodules in basalts.
Sanidinites, ete., in trachytes and kenytes.}
antilogous. 5 : . Olivine and pyroxene nodules in basalts.
Hornblendic inclusions in trachytes.
Plesiomorphous, homologous.
antilogous . : < . | Hornblende crystal in basalt.
Polygenous, endopolygenous.
exopolygenous . : : . ? Sanidinites in trachyte of Mt. Cis.
Pneumatogenous.
ENALLOGENOUS INCLUSIONS
Enallogenous inclusions : F : : Sandstones in the trachytes and kenytes.
Dolerite inclusions in the trachyte of Mt. Cis.
The microsanidinite in the basic rock from Hut Point may almost be considered
an enallogenous inclusion, for although it is distantly related to its host, it may be
assumed that it arose from a trachyte differentiate of the primitive magma and not from
the primary basic differentiate.
VIII. SUMMARY AND CONCLUSIONS
The following types of inclusions have been described :
Olivine Pyroxene and Gabbroid nodules in the basalts and limburgites of Hut Point.
Olivine Sanidinites and microsanidinites in the phonolitic trachyte of Mount Cis.
Biotite Sanidinites and microtinites in the kenytes. These are new to science.
Hornblendic nodules in the trachytes.
Doleritic inclusions in the trachyte of Mount Cis.
Quartz-pyroxene inclusions in the trachyte of Mount Cis.
Sandstone inclusions in the kenytes.
Miscellaneous erratics, presumed to be inclusions.
Only a limited number of the above types are of sedimentary origin, but those that
do occur have an important bearing on the question of the formation of the Ross Sea.
Since they are all metamorphosed sandstones, it follows that parts, at least, of Ross
Island are underlain by a sandstone formation. This can scarcely be anything else
than a down-faulted portion of the Beacon Sandstone. The presence of dolerites as well
as sandstones in the trachyte of Mount Cis strengthens this conclusion, since sills of
dolerites have been found to be ubiquitous in the Beacon Sandstones of the mainland.
All the other inclusions are of igneous origin and genetically connected with the
alkaline rocks of Ross Island. Many of them are types not met with at the surface as
separate rocks, viz., peridotites, gabbros, pyroxenites, orthophyric trachytes, sanidinites,
microtinites, camptonites, and an orbicular augite syenite. Their study thus gives
some idea of the deep-seated rocks whose formation has accompanied the eruption of
the lavas. A fuller idea of the possible differentiates of such a magma as the funda-
mental alkaline magma of Ross Island is thus obtained, and more direct comparisons
are possible with areas of deep-seated rocks.
* The inclusions of which the host is unknown cannot of course be classed.
+ If the slight amount of differentiation be overlooked.
I s
148 THE INCLUSIONS OF THE VOLCANIC ROCKS
In conclusion the writer desires to express his thanks to Professor David and
Mr. Raymond E. Priestley for unfailing kindness and assistance in the preparation of
this report, and to Messrs. Priestley and G. Burrows for assistance in the preparations
of the illustrations.
EXPLANATION OF THE PLATES
PLATE I
Ficure 1.—Olivine nodule, Hut Point. x N.* x 34 diams.
Ficure 2.—Anorthoclase in glass at edge of sanidinite, Mount Cis. x N.
Figure 3.—Sanidinite in trachyte, Mount Cis; showing egirine-augite moulded on
felspar. Not x N.
Ficure 4.—/®girine-augite in diuse cavity in sanidinite, Mount Cis. Not x N. x 27
diams.
Figure 5.—Microlitic ground-mass of sanidinite in Mount Cis trachyte. x N. x 37
ciams.
Figure 6.—Microsanidinite in trachyte, Mount Cis. x N. x 34 diams.
PLATE II
Figure 1.—Sanidinite in Cape Royds kenyte. x N. x 27 diams.
Figure 2.—Sanidinite in Cape Royds kenyte showing rounded character of anortho-
clase and titaniferous augite on the margin. Not x N. x 14 diams.
Ficure 3.—Zoned plagioclase of microtinite in the kenyte of Tent Island. x N. x 12
diams.
Figure 4.—Sanidinite from Mount Cis suggesting an aggregation of phenocrysts.
Hand-specimen.
Ficure 5.—An erratic from Cape Royds. Probably a partially remelted sanidinite
showing sanidine, leucite, magnetite, and brown glass. Not x N. x 18 diams.
Ficure 6.—Camptonitic inclusion in trachyte, Cape Bird, showing analcite and calcite
in an amygdule. Not x N. x 37 diams.
PLATE III
Figure 1.—A doleritic inclusion in trachyte, Mount Cis. x N. x 27 diams.
Figure 2.—A doleritic inclusion in trachyte from Mount Cis, showing augite and
glass with idiomorphic felspars.
Figure 3.—A quartz pyroxene inclusion in the trachyte of Mount Cis. x N. x 18
diams.
Figure 4.—A quartz xenocryst in the trachyte of Mount Cis, surrounded by a zone
of glass with egirine needles. x N. x 37 diams.
Figure 5.—A sandstone inclusion with slaggy exterior in the trachyte of Mount Cis.
Hand-specimen.
FIGURES IN THE TEXT
FicurE la.—Augite in camptonitic inclusion of Mount Bird trachyte, magmatically
resorbed with separation of magnetite and formation of a hornblenderim. Enlarged.
FicurE 1b.—Ditto: Hornblende replacing augite on one side only.
Figure 2.—Sketch of polished face of orbicular augite syenite; erratic from near
Mount Cis. Enlarged.
%*
x N = Nicol prisms crossed.
I
x
4
PLATE
ay
»
o
BG.
6
Fic.
8
14.
p-
"o face
[7
PEATE, It
PLATE III
APPENDIX TO PART VIII
JGIRINE-AUGITE CRYSTALS
FROM A MICROSANIDINITE OUT OF THE TRACHYTE
FROM MOUNT CIS, ROSS ISLAND
(With Four Figures in the Text)
BY
Miss F. COHEN, B.A., B.Sc.
THE crystals* are all very small, but distinctly prismatic im habit, with a squarish
cross-section—average measurements being roughly $ by $ by1 mm. in the direction of
the a, b, and ¢ axes respectively.
They are remarkably brittle and readily break into cleavage fragments.
Although good faces were seen embedded in the rock, those crystals that could
be isolated were unsatisfactory for purposes of measurement—the faces being nearly
all corroded and the extremities of the crystals always more or less broken.
Three crystals were examined, all of which possess the a and 6 pinacoids and the
m(110) prism. In all, m is by far the largest face and gives good readings.
The mean angles of the observed forms are tabulated below along with the
theoretical values deduced from the calculated elements.
Forms Measured Calculated
p p p
a 100 OP” ay C= OY OO” (0% 90° 0’
b 010 OO OY 90° 0’ Orn ay 90° sO’
m 110 43° 38’ 90° (O’ 43° 38’ ay
on itil 54° (197 45° 50’ 54° 507 AGS A
@ iii Q4° 38’ 33° 957 26° 00’ 330) 44%
0 221 35° 08’ 55°55’ 35° 46’ Eine = aye
@ Oli 94° 5A’ 33° 35’ OYIeY Taioye 33° 307
z 021 102 2Gy 49° 47’ 1S On? BOS Die
Of these forms one crystal} possessed a, b, m, u, s, 0, and z(Figs. 1 and 2), and another
only a, b, m, s, e(Figs. 3 and 4).
* Vide Dr. Thompson’s paper, ante.
+ The back of the crystal was broken so that other forms may have been present.
II 149 x
150 ASGIRINE-AUGITE CRYSTALS
a
Fic. 2
a
Fic. 3 Fic. 4
ANGIRINE-AUGITE CRYSTALS 151
The presence of the forms z and e is remarkable, as they apparently have not been
observed on eegirine, though they commonly occur on iron-rich diopside.*
The edges between m and u and m and z are bevelled—no signal could be obtained
from them, so that they are probably due to corrosion.
The elements calculated from the above forms gave the following results :
a:b: ¢ =1°08909 : 1: 0°600116.
Cra 23
_ * Zambonini, F., ‘ Die Morphotropischen Beziehungen zwischen Enstatit, Diopsid, Hedenbergit,
Agirin und Spodumen,” Zeits. fiir Kryst., xlvi, 1909, pp. 1-72.
PART IX
REPORT ON THE PETROLOGY OF THE
DOLERITES
COLLECTED BY THE BRITISH ANTARCTIC
EXPEDITION, 1907-1909
(With Plate)
BY
W. N. BENSON, B.Sc.
Tue dolerites of South Victoria Land extend over a wide area. They are developed
in the Royal Society and Prince Albert Ranges, on the western margin of the Great
Ross Barrier and the Ross Sea. They have been proved in the Mount Nansen region
and in the Ferrar Glacier valley to extend to more than sixty miles from the coast.
An examination of the inclusions in the lavas of Mount Erebus show that they underlie
Ross Island, and moraines on the flanks of the mountain itself contain many dolerite
erratics, probably brought from far to the south. They also occur in the moraines
on the mainland. Pebbles of dolerite similar to these here described have been dredged
up off Cape Wadworth, and to the south of the Balleny Islands. The dolerites occur
in dykes, necks, and sills in the basement complex, and form huge sills up to two thousand
feet in thickness in the overlying Beacon Sandstones. They have been met with to a
height of seven thousand feet above sea-level.
The collections of the expedition of 1901-1904 were examined by Dr. G. T. Prior,
and the following notes may be considered as supplementing his descriptions.* The
material studied by the present writer was collected chiefly from the moraines at Cape
Royds, on Ross Island, but a few specimens were submitted from the Stranded Moraines,
the Ferrar Glacier valley, and at points visited by the northern party. Several interesting
features have been noted that were not mentioned in the previous report. Chief among
these is the abundance in the quartz-dolerites of the peculiar pyroxene enstatite-augite,
the occurrence of rhombic pyroxene in granular and porphyritic varieties, and in the
presence of a passage rock into the essexites.
A convenient subdivision of the rocks studied is into the phaneric and aphanitic
groups. The former have a medium grain-size, with an ophitic or gabbroid structure ;
certain of them are distinctly porphyritic, through the development of phenocrysts of
pyroxene or plagioclase. The aphanitic rocks are very finely grained and have a granu-
litic structure, occasionally becoming slightly ophitic.
The rocks are composed essentially of basic plagioclase and pyroxene, chiefly mono-
clinic, with a varying amount of a micropegmatitic intergrowth of quartz and felspar
occurring interstitially. They thus correspond to the Hunne-diabas of Térnebohm, but,
* To be in the forthcoming Geological Memoir of the Expedition, The National Antarctic
Expedition, 1901-4, vol. i, pt. ii, chap. v.
Il 153 ¥
154. REPORT ON THE PETROLOGY OF THE DOLERITES
following the British usage adopted by Dr. Prior, they are here termed quartz-dolerites.
In addition there are quartzless and other types of dolerite. Throughout the proportion
of the felspar to the pyroxene is fairly constant, the former being slightly, more rarely
strongly, in excess.
The plagioclase as a rule is subidiomorphic, occurring in thick platy forms, sometimes
with well-developed terminal faces. Its greatest extension is in the 010 plane. The
twinning is, as remarked by Dr. Prior, almost always after the Carlsbad law, less
commonly on the albite plan. Pericline twinning is infrequent, and is most noticeable
on the larger crystals. A single example was noticed of Manebach twinning, the crystal
being also twinned on the albite and Carlsbad laws. Zoning is common. When it is
well developed, the kernels of the plagioclase crystals, which occupy about half their
area, are very basic, approximating in composition to Ab;An,;. Successive zones
rapidly decrease in basicity, the change being most rapid near the periphery. The
outermost zone has the composition Ab,;An;;, but from it still more acid extensions
may pass out into the micropegmatic material. There is never any reversal of the
change, an outer zone being invariably more acid than an inner one, showing an unin-
terrupted change of conditions in the magma during consolidation. It is rarely that
there is no sign of zoning; the most nearly homogeneous crystals have the composition
of basic labradorite. As a rule the plagioclase is free from apatite and quite fresh.
The first alteration product to appear is chlorite, which is brought into the cracks of
the felspar by solutions deriving their material from the pyroxene ; the purely felspathic
decomposition product, sericite, is seen in a few instances only. Occasionally there is a
development of very fine cavities filled with liquid, but it is not certain that these are
of secondary origin.
The pyroxenes of these rocks present many features of interest. Both the rhombic
and monoclinic pyroxenes are present in abundance, and these are developed in several
ways. In certain rocks they occur separately as bronzite or enstatite and augite. From
these there are passage rocks into those in which the two minerals occur together
in regular or irregular micrographic intergrowth. A third manner of joint oc-
currence is In isomorphous mixture with each other, forming the peculiar enstatite-
augite.
a some rocks, in particular that from the moraine on the Knob Head Mountain,
in the Ferrar Glacier valley, the enstatite under crossed nicols has a peculiar appearance,
recalling that exhibited by anorthoclase. When the vertical axis is placed parallel to
the plane of the polariser it is seen that the extinction is slightly undulose, and there
appear a number of exceedingly minute needle-like portions that are not in exact extinc-
tion ; this is possibly due to an almost submicroscopic multiple twinning. The bronzite
shows the characteristic pinkish to greenish pleochroism, but in no instance is there
any schiller structure. When rhombic and monoclinic pyroxene occur separately the
thombic seems rather the more nearly idiomorphic, though both may be ophitic. When
they are intergrown the enstatite or bronzite forms the matrix, and small strips of augite
may be scattered about in it quite irregularly, and without any definite orientation or
shape. In other cases there is a definite orientation; the augite may form two sets
of strips in optical continuity with each other, and elongated parallel respectively to
the basal plane and vertical axis of an augite skeleton crystal ; and this augite skeleton
crystal, composed thus of rods, plates, and hook-like pieces, is oriented in the rhombic
crystal so that its vertical axis coincides with that of the latter. When the augite
skeleton is twinned, the two sets of stripes parallel to the basal planes form a herring-
bone pattern in the rhombic crystal. In some instances there may extend from a
twinned augite kernel thin lamelle of augite, running parallel to its basal plane out
into the surrounding rhombic pyroxene (Plate I, Fig. 2). This intergrowth of pyroxenes,
REPORT ON THE PETROLOGY OF THE DOLERITES 155
“ pyroxene-perthite,” occurs in a few instances in the phaneric rocks and is best studied
there, but it is almost always present in the aphanitic dolerites. Parallel growth of the
two pyroxenes without definite intergrowth is also a marked feature of some of the
porphyritic rocks (see Plate I, Fig. 3).
Enstatite-augite * is the normal pyroxene in the phaneric quartz dolerites. It forms
large grains, ophitic to roughly prismatic in habit, and of a pale purple-grey colour.
It is frequently twinned on the 100 plane, usually singly only. Besides the prismatic
cleavages there is often a marked striation parallel to the basal plane, due partly to the
presence of a very fine cleavage in that direction, but also to twinning developed on
a very minute scale. It is only in a few favourable instances that these lamelle are
sufficiently thick to be clearly seen. Twinning on the 100 plane gives rise to the herring-
bone structure, in which the striations on one side of the twining plane stand at an
obtuse angle to those on the other. The extinction angle ¢ to ¢ does not vary greatly,
being between 40° and 45°, but the optic axial angle 2E varies very much. In the
same slide crystals may occur, the optic axial angles of which vary from 90° to 0°.
The most frequent values are those lying between 0° and 30°, and from 65° to 90°.+
Values intermediate to these have been noted but are rare. In sections of ordinary
thickness there is no sign of pleochroism.
The normal augites in which the optic axial angle is large occur in those rocks in
which rhombic pyroxenes are abundant, and in those that are free from micropegmatite.
In the latter they are usually very ophitic.
The alteration of rhombic pyroxene commences with the development of pale-green
fibres parallel to the vertical axis, and growing in from the periphery, and from the
irregular cracks which traverse the crystal. A completely altered enstatite recalls the
appearance of serpentinised olivine. The alteration of enstatite-augite, and sometimes
of normal augite, commences with development of fibres parallel to the basal striation,
greenish-brown in colour, and probably chlorite. With increasing alteration a dense
mat of fibres is formed, sometimes with an irregular, though sharply defined, outline.
In apparently unstriated grains the alteration may commence in the centre and is
accompanied by a decrease in birefringence. Very finely divided carbonate material
is sometimes developed with the chlorite fibres. Sometimes brown mica is produced,
possibly by interaction with the felspar ; it forms small flakes and rosette-like aggregates.
These latter forms of alteration are those that affect the normal augite most. In the
pyroxenes there are frequently minute liquid-filled cavities, but it 1s not certain that
these are of secondary origin.
Iron ore occurs in varying amount, either in irregular grains or as plates ; it is nearly
all ilmenite. It is nearly always present in the aphanitic dolerites, but occurs less
frequently in the phaneric rocks. Biotite is sometimes present in small red-brown
flakes. In one instance only is it present in notable amount.
In the intergranular spaces of the rock there is frequently a micropegmatitic inter-
growth of quartz and felspar. The coarseness of grain of this is often proportional to
that of the rock itself. The felspar may be fresh or clouded, and has a lower refractive
index than Canada balsam ; generally it is recognisable as orthoclase. In a few instances,
however, it appears as apophyses from the plagioclase crystals, more acid than their
outermost zone, and may therefore be albite. A second type of mesostasis is sometimes
seen, particularly in certain rocks collected by the Magnetic Pole party. This is very
much finer in grain-size. It is composed of cloudy orthoclase, containing thin strips
of a clear colourless mineral, more strongly refractive, and disposed in parallel bundles
* W. Wahl, “ Die Enstatitaugite,” Tschermak’s Min. und Petr. Mitt., Bd. xxvi, pp. 1-131.
+ These figures are rough approximations only.
156 REPORT ON THE PETROLOGY OF THE DOLERITES
or in subradiating groups. It is difficult to determine whether these are quartz or not.
The intergrowth is identical in character with that forming the mesostasis of the enstatite-
augite bearing rock of Launceston in Tasmania, and in this Professor Ossan * considers
the clear strips to be andesine on account of their refractive index and birefringence
being identical with that of the outer zone of the plagioclase crystals, to which they
are sometimes parallel both in extension and optical orientation, Nevertheless a little
free quartz in irregular grains is sometimes associated with this intergrowth.
Apatite is present in very small amount only, and occurs almost exclusively with the
micropegmatite.
The general type of the phaneric erratics of Cape Royds and that at the pseudo-Cape
Irizar is semi-ophitic in texture, and is composed of basic zoned plagioclase, enstatite-
augite, and a varying amount of interstitial micropegmatite. In addition there may
be a small amount of biotite and ilmenite. In some instances the amount of micro-
pegmatite may be very great (see Plate I, Fig. 1). In another variety with a slightly
porphyritic habit both monoclinic and rhombic pyroxenes are present; the latter is
the more abundant. Its pale pink to green pleochroism prove it to be bronzite. The
monoclinic pyroxene is the more ophitic in habit, and its optic axial angle is large.
A certain amount of pyroxene perthite is present regularly and irregularly developed.
A little biotite, ilmenite, and a fair amount of micropegmatite are also developed. In
a somewhat similar rock enstatite-augite occurs with the rhombic pyroxene, sometimes
in parallel growth. No. 1545 is strongly porphyritic. The bronzite crystals are up to
four millimetres in length ; the monoclinic pyroxene, enstatite-augite, is less abundant,
ophitic, and with a small optic axial angle ranging from 20° upwards. The plagioclase,
labradorite, is slightly zoned, and is present in small tabule and a few phenocrysts. The
chemical composition of this rock is given on page 157 (No. 1).
The rock collected by Priestley from the Knob Head Mountain moraine in the Ferrar
Glacier valley is a most beautiful rock, and is quite distinct from that obtained from
the mountain itself by Ferrar. It shows in hand-specimen a cloudy white felspar matrix
studded with phenocrysts of yellow-brown enstatite. Under the microscope the plagio-
clase appears to be in very small crystals, though there are some larger grains. It is
basic labradorite and is slightly zoned. Here and there are scattered through it patches
of isolated grains of colourless augite, in optical continuity. The phenocrysts of enstatite
are sometimes four or five millimetres in length, and frequently exhibit the strained
anorthoclase-like appearance before described. They are not idiomorphic, but usually
are ophitically intergrown with felspar on the periphery, and may contain felspar laths.
Sometimes also they are grown with monoclinic pyroxene in parallel position, the latter
fraying out ophitically into the felspar (see Plate I, Fig. 3).
No. P. 204 is an erratic from Cape Royds in which the ophitic structure is developed
to its highest degree. The augite has a large optic axial angle, is pale in colour, and
is commencing to alter into chlorite, which ina very few places contains a fibrous, radiat-
ing, colourless mineral with some of the optical properties of stilbite. A little ilmenite
is present, but no micropegmatite.
No. P. 242 is the alteration product of a rock similar to the above, but differing in
the presence of a little biotite and quartz. The felspar laths are changing into sericite,
the augite is passing into chlorite carbonates and secondary mica. A little magnetite
and a few apatite needles are also present.
With the phaneric dolerites may also be classed No. P. 252, a Cape Royds erratic.
It resembles the quartz dolerites in the abundance of the rhombic molecule, and the
presence of micropegmatite ; it differs in the comparative abundance of potash, as
* “ Ueber einen Enstatitaugit-fiihrenden Diabase von Tasmanien,” Centralblatt fiir Mineralogie,
1907, pp. 705-711.
REPORT ON THE PETROLOGY OF THE DOLERITES 157
shown by the presence of notable amounts of biotite and orthoclase. The rock has thus
affinities with the essexites. It is seriate porphyroid, but distinctly dopatic. It contains
hypersthene, augite, and biotite in a meshwork of felspar laths, with occasionally pheno-
crysts of plagioclase. Orthoclase and quartz occur interstitially, and a little apatite and
ilmenite are present. Basic labradorite is the predominant mineral, hypersthene the
more abundant pyroxene, strongly pleochroic and slightly decomposed. Biotite forms
irregular flakes, and in one instance appears to be mtergrown with hypersthene. A
very little brown hornblende occurs on the border of some of the hypersthene crystals ;
it 1s possibly secondary. The interstitial orthoclase is sometimes intergrown with
quartz. A few octahedra of magnetite are present (see Plate I, Fig. 4).
Erratic No. 1100 is the only sample of a hypocrystalline rock submitted. It is
strongly ophitic, the pyroxene, the optic axial angle of which is near 90°, being very
much divided by the felspar mesh. Irregularly shaped areas occur made up of a dark-
brown glass, partly altering to chlorite, and containing idiomorphic or skeleton felspar
crystals and a large amount of magnetite, as skeleton crystals or dust. Some plagio-
clase phenocrysts are developed (see Plate I, Fig. 5).
The aphanitic dolerites are all very fine in grain. They are dark greenish-grey in
colour, translucent on thin edges, and in general appearance somewhat like hornfels.
They are holocrystalline, with an average grain-size of about 0-1 millimetre in diameter.
The structure is granulitic ; small grains of pyroxene, either irregularly equidimensional
or slightly prismatic, lie enclosed in a meshwork of felspar tabule of rather smaller size.
The Chemical Composition of Dolerites from South Victoria Land
I. Erratic No. 1545, Cape Royds ; Porphyritie quartz-dolerite with bronzite.
II. Erratic No. P. 366, Cape Royds; Aphanitie quartz-dolerite.
III. Quartz-dolerite from Knob Head Mountain; analysed by Dr. G. T. Prior.
IV. Enstatite-augite bearing diabase from Launceston, Tasmania; analysed by Professor
Dittrich.
V. Konga-diabase from North-West Bay, Tasmania; analysed by Dr. Pohl.
VI. Quartz-diabase from the Cuyuni River, British Guiana.
158 REPORT ON THE PETROLOGY OF THE DOLERITES
There is no trace of any porphyritic structure or sign of flow in any of the rocks submitted
for examination. From the granulitic structure there are gradations into the ophitic,
developed to some extent in a few specimens. The plagioclase, basic labradorite, is
in short thick tabule, mutually interfering, but idiomorphic against the micropegmatite,
less commonly against the pyroxene. Both rhombic and monoclinic pyroxenes are
usually present. The former, bronzite, is generally rather more nearly idiomorphic.
A microperthitic intergrowth of monoclinic pyroxene is very frequent, usually regularly
oriented, and often showing single or multiple twinning on the 100 plane, giving a herring-
bone or zigzag pattern. The monoclinic pyroxene has a large optic axial angle, and
the extinction ¢ to C is about 45°. It is slightly striated and rarely twinned. Varying
amounts of ilmenite and biotite are present, the former in small plates, the latter in
irregular flakes usually moulded on the ilmenite. A few exceedingly small prisms of
apatite are present. A varying amount of a very fine-grained micropegmatite occurs
interstitially. All the aphanitic dolerites examined were erratics from Cape Royds,
and nearly all were quite fresh. Plate I, Fig. 6, is very typical of these rocks.
The chemical composition of South Victoria Land dolerites will be seen from the table
on p. 157.
On calculation the first two analyses give the following “ norms ” :
I II
Quartz 4 . 5 7-26 AG 6-18
Orthoclase . ‘. : 5 2-78 aie 6:12
Albite : 5 é 0 10-48 me 13-62
Anorthite . é 5 3 33°36 oe 30-86
Diopsite . ; : c 7-34 30 17-50
Bronzite . A a ‘i 35°82 Ke 22-54
Ilmenite . A 4 ; 1:22 See 137.
Magnetite . ; : : 1-62 5.6 1:16
Water 3 a 4 0:70 Ae 0:56
100:58 99-91
Both of these fall into the division ITT, 1.4.4.3. of the American classification, being
slightly more acid than the rock analysed by Dr. Prior, which is an Auvergnose III, 1.5.4.3.
The study of these rocks may throw some light on the origin of quartz-dolerites.
Several hypotheses have been advanced to account for this. One would consider the
micropegmatite to have been derived by intrusion of granophyre into the consolidating
dolerite, urging in support the frequent association of soda-aplites or granophyres with
quartz-gabbros or dolerites. A second considers the rocks to be produced by a mixture
in varying proportions of a granophyric with a gabbroid magma. A third would derive
the granophyre from the gabbroid or magma by differentiation through fractional crystal-
lisation ; the acid residuum either forms the granophyric mesostasis in the rock or is
extruded from it to form the dykes of granophyre. Dr. Prior points out that the general
variation of the grain-size of the micropegmatite with that of the including rock is the
fact used by Dr. Holland in support of his application of the third hypothesis to the
explanation of the micropegmatite in the Indian “ augite-diorites.” * The rarity or
absence of veins and dykes of soda-aplite or granophyre in the dolerite masses of South
Victoria Land may also be taken to show that their presence is not essential to the formation
of quartz-dolerites. But some rocks occur, like certain collected on the Dry Valley
by Ferrar, and by the Magnetic Pole party in 1908-9, in which the acid material is very
* G. T. Prior, loc. cit. supra, p. 186.
REPORT ON THE PETROLOGY OF THE DOLERITES 159
fine grained, felsitic, and in patches so distinct from the rest of the rocks as to suggest
a mingling of two rock types.
Another point of interest is the widespread distribution of quartz-dolerites, occurring
under conditions analogous to those found in the Antarctic. In Tasmania, South Africa,
and in parts of South America quartz-dolerites are found forming sills in sandstone
and other formations which have intruded during the Mesozoic period.
In particular the similarity between the occurrence of dolerite in Tasmania and
South Victoria Land is so striking as to strongly support the view that the two areas
form part of a geological unit. ‘Tasmania is chiefly composed of an almost horizontally
bedded series of sandstones, coal-measures, mudstones, and limestones of Mesozoic and
Permo-carboniferous age, lying on a strongly folded complex of Silurian and older
rocks intruded by granite. In Cretaceous times came the intrusions of dolerite,* which
formed great sills in the Permo-carboniferous and particularly in the Mesozoic sand-
stones. After the intrusion the area was broken considerably and differentially elevated
with block-faulting. Erosion has now exposed the dolerite which occurs, capping nearly
every important elevation in the island. The geology of the Tasmanian and Antarctic
dolerite is thus very similar, and the physiography of the two areas is remarkably constant.
Microscopically there is also a strong resemblance between the rocks. Dr.Woolnough first
drew my attention to the similarity of the Launceston rock to some of the Antarctic dole-
rites, and the examination of a series of Tasmanian dolerites, kindly sent by Mr. W. H.
Twelvetrees, the Government Geologist of Tasmania, fully bears this out. Enstatite-augite
has been noted in rocks from several other localities than Launceston, in which it was
discovered by Professor Osann, and may be taken to be of fairly general occurrence.
The mesostasis is usually of the fine-grained felsitic type, but coarse-grained micropeg-
matite was noted in a rock from North-West Bay by Dr. F. P. Paul + (see Analysis V).
The biotitic variety of dolerite from the Antarctic may have its parallel in the biotitic
rock from Dundas described by L. K. Ward.t
A further point of similarity is in the general absence of olivine from the two areas.
The analyses given (Nos. IV and V) are the only ones of Tasmanian dolerites that are
available ; they would indicate that the percentage of magnesia was less than in those
of the Antarctic. According to Mr. W. H. Twelvetrees, in Tasmania also there is an
absence of veins of granophyre from the dolerite masses.
In South Africa the dolerites were intruded in Jurassic times into the horizontal or
slightly folded beds of the Karoo system, in which they form huge sills up to two thousand
feet in thickness. “The constituents are plagioclase, felspar, augite, olivine, and
magnetite in the relative order of their abundance; but olivine is not infrequently
absent. In addition, biotite may be present and sometimes original hornblende, either
independently or in close connection with the augite. In the more acid types quartz
and occasionally orthoclase felspar are present, often in the form of micropegmatite.” §
In certain of these dolerites Wahl has noted the presence of enstatite-augite. The
chemical composition of the dolerites is very uniform, but the analyses given by E. Cohen
are invariably much higher in ferric oxide and lower alumina than those of Antarctic
* Tt should be remarked that the Tasmanian geologists follow the German usage in terming
these rocks “ Diabase.” For a general description of their mode of occurrence and petrology
see W. H. Twelvetrees and W. F. Pettard, Proceedings of the Royal Society of Tasmania, 1898-99,
p- 47, and W. H. Twelvetrees, ‘‘ The Igneous Rocks of Tasmania ” Report of the Australian Asso-
ciation for the Advancement of Science, 1902, p. 287.
+ “ Beitrage zur-petrographischen Kenntniss einiger foyaitischentheralitischen Gesteine aus
Tasmanien,” Tschermak’s Min. wnd Petr. Mitt., Bd. xxv, p. 267.
{ Tasmanian Geological Survey, Bulletin No. 6, p. 28.
§ A. W. Rogers and A. L. Du Toit, The Geology of Cape Colony, chap. ix.
160 REPORT ON THE PETROLOGY OF THE DOLERITES
and Tasmanian rocks. As there is nothing in the brief description cited above to suggest
any great excess of magnetite, some suspicion is thrown on the correctness of the figures
given for these oxides. Otherwise the analyses are not unlike those of Tasmanian rocks.
In British Guiana, overlying the basement complex, there is an extensive series
of almost horizontally bedded sandstones, which continue across the borders into
Venezuela and Brazil. They are barren of fossils. In the last two countries there is
evidence for believing them to be of Cretaceous age, but C. B. Brown considers them to
be Triassic on the grounds of their great lithological resemblance to the sandstones of
that age in North America. They are intruded by dykes and sills of dolerite (“ diabase ”’),
which are of Cretaceous or Tertiary age, and Harrison leans to the latter alternative.*
In microscopical features they are very similar to the Antarctic, and the comparison of
the analyses quoted (No. VI) of the rock from the Cuyuni River with that made by
Dr. Prior (No. II) will show how very similar are the two rocks in chemical composition.
In this connection might also be noted the occurrence of quartz-dolerites in the
Mesozoic Newark system near New York, of which the famous Palisades on the Hudson
area part.| Wahl has shown that enstatite-augite occurs in these rocks, and they have
other features analogous with those of the rocks here considered.
The author’s thanks are due to Professor David and Mr. R. E. Priestley for the
opportunity of examining these rocks, and to Mr. Allen Thomson for his assistance.
SYDNEY
December 1910
* See J. B. Harrison, The Geology of the Goldfields of British Guiana, p. 28, and also chap. x.
+ See J. V. Lewis, “ Palisade Diabase of New Jersey,” Amer. Jour. of Science, vol. elxxvi, 1908,
p- 155; “‘ Structure on Correlation of the Newark Trap Rocks of New Jersey,” Bull. Geol. Soc. of
America, vol. xvii, pp. 195-210; “ Origin and Relations of the Newark Rocks,” Ann. Rept. State
Geologist of N.J. for 1906, pp. 97-129.
EXPLANATION OF THE PLATE
Figure 1.—Plagioclase crystal surrounded by quartz and felspar micropegmatite.
Erratic P. 363 from Cape Royds. Polarised light, magnified 1:45 diameters.
Figure 2.—Intergrowth of a twinned augite crystal in enstatite. Erratic No. 93 from
Cape Royds. Polarised light, magnified 26 diameters.
Ficure 3.—Parallel growth of ophitic augite and enstatite. The darker central portion
of the pyroxene crystal is enstatite, the lighter surrounding portion augite, showing
basal striation. Erratic No. P. 82. Knob Head Mountain moraine. Polarised
light, magnified 26 diameters.
Figure 4.—Kssexite dolerite showing hypersthene and biotite, the latter in dark basal
sections and lighter vertical sections. Erratic from Cape Royds. Ordinary light,
magnified 26 diameters.
Figure 5.—Hypocrystalline ophitic dolerite. Erratic No. 1100 from Cape Royds.
Ordinary light, magnified 26 diameters.
Figure 6.—Aphanitic dolerite. Erratic No. P. 366 from Cape Royds. Ordinary light,
magnified 26 diameters.
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PART X
REPORT ON THE PYROXENE GRANULITES
COLLECTED BY THE BRITISH ANTARCTIC
EXPEDITION, 1907-1909
(With Plate)
Bia
A. B.. WALKOM, B.Sc.
THE pyroxene granulites described in this paper were all erratics collected at Cape
Royds. They are very similar both in hand-specimen and mineral composition to
similar rocks which have been described from other parts of the world, viz., Saxony,
Canada, Ceylon, Madagascar, etc. Garnet, which is a very common constituent of
these rocks in other parts, is quite absent from this series, while sphene, which is not
common in other areas, is a very constant constituent here.
These rocks, occurring as they do in the form of erratics, cannot be expected to
throw much hight on the nature of their origin.
Analyses of two of them have been made by Mr. G. J. Burrows, B.Sc., and myself,
with the following results :
I II
Erratic No. 96. Erratic No. 584.
SiO, Ree ee SSL he, Ae ray ae 7 i70
AOL 2 sae 5 8:37 2 6:90
Fe,0,; . ; 0-95 fe 0-96
FeO : . > 2 5 : A 3°37 26 374
MnO : : : ‘ : ‘ , 0:09 we 0°05
MgO : : ‘ ; : : ; 2°52 fs 2°82
CaO 4 ¢ ‘ c : 5 5°19 5 ai 1137
Na,O : : ‘ ; : : ; 2-09 “8 0°66
K,O : é F ; : : 6 1°31 ap 0°10
oer. : : ; : 4 0°30 ee 0°22
‘Ora ; : 4 é : 0°26 ba 0°08
TiO, ; a: i ae 1:10 i ian
P.O, : : : : : : : 0°57 A 0:09
COs : : ‘ : F ; 5 = ‘ie trace
ZrO, : j : : : : : trace eC lmOzG
100°79 less ‘04 as O for Cl
99°92
These analyses differ considerably in some respects from those published of other
similar rocks. The most noticeable difference is in the case of the relative proportion
of CaO to SiO. In all similar rocks with a percentage of SiO, greater than 70 the CaO
rarely goes as high as 2 per cent. and never above 3 per cent., yet in the case of both
the present analyses it is considerably above this amount, and in the second of these
II 161 Z
162 THE PYROXENE GRANULITES COLLECTED
analyses it has an exceedingly high percentage, viz., 11°37. This high percentage of
lime is justified by the fact that all the minerals of the rock (quartz excepted) contain
a considerable amount of CaO. The alkalies are fairly normal in analysis No. I, but
are almost absent in No. II, their place here being taken by the CaO. The analyses
strongly suggest that these rocks belong to Rosenbusch’s group of Para-gneisses.
The pyroxene granulites are typically of a greenish colour—some light green and
others much darker. They are fine-grained to medium-grained, and the grains are
very even in size. They are very hard, much silicified, and have a somewhat greasy
lustre. The degree of foliation varies considerably ; in some of them there is no folia-
tion present, while in others it is very well marked. The fracture is always smooth
and approaches conchoidal. Some of the constituent minerals can generally be identified
in hand-specimen—-notably quartz and sometimes felspar. The ferro-magnesian
mineral, too, is generally recognisable as such, though its more exact determination is
difficult. The light- and dark-coloured minerals are distributed fairly evenly throughout
the rock, and in a few cases there are coarse veins of quartz running through the hand-
specimens.
These rocks may conveniently be divided into three classes, as follows :
(1) Acid pyroxene granulites.
(2) Scapolite-bearing pyroxene granulites.
(3) Basic pyroxene granulites.
The acid pyroxene granulites are those in which quartz is present in large quantity.
The presence, in fair amount, of scapolite in a number of the rocks has led to their
being classed together as a separate group. The basic pyroxene granulites are those
in which quartz is absent or only present in subordinate amount. Jt is somewhat
difficult to place definitely the dividing-lme between the acid and basic groups. The
amount of quartz present decreases fairly regularly from the most acid down to those
where it is quite absent.
The mineralogical composition of these rocks is shown in the table on p. 163. .
(1) THE ACID PYROXENE GRANULITES
This class includes those granulites in which quartz is present in abundance. The
constituent minerals are quartz, pyroxene (monoclinic), felspar, sphene, zircon, apatite,
magnetite, sericite, and carbonate. The quartz, in almost all cases, shows shadowy
extinctions and has suffered a certain amount of granulation. The pyroxene is in
all cases monoclinic. It is colourless and only exhibits a shght amount of absorption.
Tt is characterised by a fairly uniform high extinction (35° to 40°) and 2V is large. It
is, then, almost certainly, diopside. The pyroxene is the same throughout both the
acid and basic groups and also in most of the scapolite-bearing group. The felspar is
plagioclase, and where suitable sections for its specific determination are present it 1s
found to be labradorite. Sphene and zircon are constant members, and occur in
characteristic forms. Apatite, magnetite, and biotite are occasional constituents.
Sericite and carbonate, and possibly also some of the biotite, are secondary.
96. PyROxENE GRANULITE, ERRATIC (Cape Royds).
In hand-specimen this is a dark-coloured rock, very hard and much silicified. It has
a smooth, conchoidal fracture. It is extremely fine-grained and is noticeably banded.
Quartz and a light-greenish ferro-magnesian mineral can be recognised and also occasional
small flakes of biotite. ;
Microscopically the rock is seen to have a granulitic fabric ; there is a tendency to
BY THE BRITISH ANTARCTIC EXPEDITION, 1907-1909 163
lepidoblastic structure owing to the biotite occurring in flakes, but the distribution of
the flake does not point to any foliation in the rock.
The constituent minerals are: quartz, felspar, biotite, pyroxene, sphene, magnetite,
and apatite.
Quartz is easily the most abundant mineral. It is in allotriomorphic grains, and
shadowy extinctions are very prominent. It does not appear to be granulated to any
extent. The felspar is not very abundant and is mostly untwinned. It is quite fresh
but has numerous minute inclusions. _Biotite is fairly plentiful in small ragged, elongated
flakes, and gives the rock a somewhat lepidoblastic appearance. In some cases it is
decomposing, the brown colour being altered to green and the D.R. slightly decreased,
thus showing change to chlorite. Pyroxene is present in colourless allotriomorphic
bunches. It is diopside. Sphene is present in fair quantity. It is in small characteristic
sections, and these have a tendency to cluster together in bunches. Zircon, apatite,
and magnetite are sparingly present. For an analysis of this rock see p. 161.
MINERALOGICAL COMPOSITION OF ROCKS
Number é Fe g €
. of Locality. s| 6 e 3 = e g = 3g £ S
Specimen. Fee i) eae |) = || AE5 | Sebi) eee || GE, || ee
pt) SS |! es || oy | aS | a= Breese eat ues salt cs
CG) A & NM mi N <q) 4 | mi) | oO
96 Erratic. Cape Royds XRG ERS | Xs DG |d-G 1) 2-S | 8
1684 se 5 NG! |) D.G 1D. GID. Glos x XxX
T = ee ie = ibs is
960 DG (Cb DENS Xeni Xe
Acid -
Pyroxene 1537 A > Saline: Sal > Salbes xX de
Granulites - — S -
P. 376 XCM Near |e Xce | mes xe x ».@
1865 aXe eX xe xX
249 DGPS [>| | OG 6 Xi
II
584 Del. pl. Eal |- 9 |. x
Ss lite- : z
tae P 391 Al ee | kee x
bearing
Pyroxene fa : z a : > 5 pes eel
Granulites 12) hats) >, XE || SX |) EX oS ? Dial ie ge
459 SCM DG |] Doo OE9 | ae xX
| 1267 Xe exe sex x
Til
1515 XG EXON | eaXe
Basic =
Pyroxene e26 xs XE || VEX || EXE ||, EXE
Granulites | — -
P. 216 ONE | Seg Nes | Xe x
164 THE PYROXENE GRANULITES COLLECTED
1684. PyROXENE GRANULITE, Erratic (Cape Royds).
In hand-specimen a dark green, greasy-looking rock; it is much silicified and is
slightly foliated. Quartz and a dark ferro-magnesian mineral can be recognised.
Under the microscope the fabric is granulitic ; the grainsize is even and medium.
A marked degree of foliation is shown by the biotite, pyroxene, and quartz. The
biotites have their longer axes in a general parallel direction, as also have the pyroxenes
to a lesser degree. The quartz grains are elongated parallel to the same direction.
The minerals present are: quartz, felspar, biotite, pyroxene, apatite, sphene, pyrites,
and zircon.
Quartz is most abundant in allotriomorphic grains. It shows shadowy extinction
and has undergone a considerable amount of granulation. Felspar is fairly abundant.
It is mostly untwinned but occasional grains are twinned after the albite law. It is
in subidiomorphic grains, slightly decomposed and with numerous inclusions. Its
R.I. is higher than that of quartz. Biotite is present in some quantity in very ragged
allotriomorphic grains. It is moulded on both the pyroxene and felspar. In most
cases where it is moulded on the pyroxene there is a fairly well-marked line of division
between the two minerals ; in a few cases, however, the line is not easily distinguished,
and it appears in these cases as if the biotite may be the result of an alteration of the
pyroxene. The minerals of the rock show considerable granulation, and this is possibly
a case of alteration such as described by Parsons.*
Pyroxene is not very abundant in colourless, allotriomorphic grains. Sphene, apatite,
pyrites, and zircon are sparingly present.
960. PyROXENE GRANULITE, Erratic (Cape Royds).
The hand-specimen is a dark-greenish, hard, and somewhat silicified rock. It is
very fine-grained and shows very little foliation. Quartz and a dark ferro-magnesian
mineral can be recognised. Under the microscope the fabric is granulitic and the
grainsize even and medium. Foliation scarcely noticeable. (Plate I, Fig. 1.)
The minerals are: quartz, pyroxene, felspar, sphene, zircon, apatite. Quartz is
in irregular allotriomorphic grains, and is easily the most abundant mineral. It is
quite clear and free from inclusions, shows shadowy extinctions, and is considerably
granulated. Felspar is abundant in subidiomorphic sections twinned mostly after the
albite law and occasionally after the Carlsbad. Its R.I. is a good deal higher than
that of quartz. Extinctions in sections perpendicular to albite twins go up to about
32°. It is then a basic labradorite. It shows shadowy extinctions; it is only very
slightly dusted with decomposition products. Pyroxene 1s in irregular-shaped grains and
columnar sections. It is colourless and without many inclusions. Sphene is plentiful and
is mostly included in the quartz and pyroxene. Small zircons and apatites are present.
1537. PyROXENE GRANULITE, Erratic (Cape Royds).
In hand-specimen a greyish-green holocrystalline rock; medium to fine-grained.
No foliation visible. Quartz is recognisable, and the ferro-magnesian mineral is a rather
light green in colour.
Under the microscope the fabric is granulitic ; grainsize even and fine. Foliation
apparent by the direction of elongation of the minerals. (Plate I, Fig. 2.)
The minerals present are: pyroxene, felspar, quartz, sphene, zircon, and carbonate.
Pyroxene is abundant in irregular grains, very light in colour. Felspar is in allo-
triomorphic grains twinned after the albite, Carlsbad, and pericline laws. The combina-
tion of albite and pericline laws gives a cross-hatching appearance very like microcline.
It is moulded on quartz and sometimes pyroxene; it is quite fresh. Extinctions in
symmetrical sections go up to 33°, and it is therefore a basic labradorite. Quartz
* James Parsons, B.Se., “* The Development of brown mica from augite, ete.,” Geol. Mag.,
1900, p. 316.
BY THE BRITISH ANTARCTIC EXPEDITION, 1907-1909 165
is abundant in irregular to rounded grains and generally free from inclusions. Sphene
and zircon are present, and also a small amount of carbonate.
P. 376. PyroxENE GRANULITE, Erratic (Cape Royds).
Hand-specimen missing.
Microscopically the fabric is granulitic and the grainsize even, medium.
The minerals present are: pyroxene, felspar, quartz, sphene, apatite, and sericite.
Pyroxene is most abundant and forms nearly half the rock. It is, as usual, in
colourless allotriomorphic grains. Mostly fresh, but occasionally it has undergone a
small amount of decomposition. The felspar is plagioclase twinned after albite, pericline,
and occasionally Carlsbad laws. It is in subidiomorphic grains with numerous inclusions :
decomposed considerably to sericite, with carbonates present as a side-product of the
alteration. Quartz is fairly abundant in allotriomorphic, somewhat rounded grains,
comparatively free from inclusions. Sphene is abundant and apatite sparingly present.
1865. PyRoxENE GRANULITE, Erratic (Cape Royds).
In hand-specimen a dark-greenish, greasy-looking rock, very much silicified, fine-grained
and hard. No foliation visible. Quartz and a ferro-magnesian mineral can be recognised.
Under the microscope the fabric is granulitic, and the grainsize even and small.
The minerals present are: quartz, pyroxene, magnetite, and zircon.
Quartz is abundant in small rounded grains. It shows shadowy extinctions ; it
has very few inclusions. The pyroxene is very light coloured and is in rather rounded
erains. Magnetite and sphene are only sparingly present.
(2) THE SCAPOLITE-BEARING GRANULITES
This division is practically a subdivision of the acid group. All the rocks in it
would, but for the presence of a fair amount of scapolite, belong to group (1). The amount
of scapolite varies considerably in the different members. The mineralogical compo-
sition of the various members of the group is very constant, the minerals being almost
the same throughout.
249. SCAPOLITE-BEARING PyROXENE GRANULITE, ERRATIC (Cape Royds). Hand-
specimen missing.
Under the microscope the rock is granulitic, consisting of small, even-sized, somewhat
rounded grains whose average diameter is about “15 mm. Occasional larger grains of
scapolite are present, and these are usually so full of inclusions as to present a “ sieve ”
structure. There is not a trace of foliation. The minerals are: pyroxene, scapolite,
quartz, felspar, sphene, and magnetite.
Pyroxene is the most abundant mineral. It is quite fresh and forms nearly half
of the rock. It is Diopside. Scapolite is present in subidiomorphic, colourless grains,
some of which show two cleavages at right angles to one another. The D.R. is high
(021 approx.) and negative and the mineral is uniaxial. The larger grains contain very
numerous small inclusions of a colourless, strongly doubly refracting mineral, which
may be sericite. Quartz is fairly abundant in irregular grains, almost free from inclu-
sions. Most of the quartz shows an entire absence of strain effects and only a very few
show shadowy extinction. The felspar is a plagioclase twinned after the albite law.
It is in fairly large allotriomorphic grains. Only a few suitable symmetrical sections
are present, and their extinctions point to its being labradorite. It is a good deal
dusted with decomposition product and in places is slightly sericitised. Sphene and
magnetite are sparingly present.
584. SCAPOLITE-BEARING PyROXENE GRANULITE, ERRATIC (Cape Royds).
The hand-specimen is a dark green mottled rock, very noticeably foliated. Quartz
and a clear green pyroxene are easily recognisable. Under the microscope the fabric
is granulitic, and the grainsize fairly even and medium. (Plate I, Fig. 3.)
166 THE PYROXENE GRANULITES COLLECTED
The minerals present are: quartz, pyroxene, scapolite, felspar, sphene, and apatite.
Quartz is the most abundant mineral and occurs in very ragged, elongated grains
which show marked shadowy extinctions. The larger grains are very much granulated.
Pyroxene is abundant in subidiomorphic grains, light green in colour, with fairly strong
absorption but little pleochroism. The D.R. is medium (about 021) and _ positive,
and the R.I. high. It is most probably augite. Scapolite (Wernerite) is present in
irregular grains. Felspar is present in allotriomorphic grains showing albite twins.
Tt is labradorite with composition Ab,An,. Sphene is abundant and apatite scarce.
This rock has been analysed and the analysis is given on p. 161.
459. SCAPOLITE-BEARING PyROXENE GRANULITE, ERRATIC (Cape Royds).
Hand-specimen. A light-greenish, fine-grained rock, fairly hard and heavy. It is
very siliceous and has well-marked foliation. Quartz, felspar, and a greenish ferro-
magnesian mineral can be recognised. Under the microscope the fabric is granulitic
and the grainsize even, medium, with the grains having an average diameter of about
‘4mm. Folation very noticeable both by the pyroxene and sphene.
Minerals present are: scapolite, pyroxene, quartz, felspar, sphene, and pyrites.
Scapolite is perhaps the most abundant mineral. It encloses pyroxene, quartz,
and sphene poikilitically. Pyroxene is abundant in subidiomorphic and rounded grains,
colourless, nonpleochroic, and with no noticeable absorption. It is Diopside. The
sections are mostly longitudinal ones and the cleavages are all in a roughly parallel
direction. Quartz is fairly abundant, with very little evidence of strain. Felspar is
not abundant. It is in fairly large allotriomorphic grains twinned after the albite law.
It is a good deal altered, and the appearance is much the same as when a felspar becomes
sericitised, with the difference that the secondary mineral, instead of being sericite, is
scapolite. The felspar is a labradorite with the composition Ab,An,. Sphene is present
as numerous small lozenge-shaped crystals. Apatite, zircon, and pyrites are sparingly
present.
P. 391. SCAPOLITE-BEARING PyROXENE GRANULITE, Erratic (Cape Royds).
Hand-specimen missing.
Under the microscope the fabric is granulitic and the grainsize uneven.
The minerals are: pyroxene, quartz, felspar, scapolite, sphene, zircon. Pyroxene
is easily the most abundant mineral and is present in rounded to columnar grains.
The rectangular cleavage is very well marked. It is colourless and quite fresh, and is
Diopside. Quartz is in irregular grains, some of which show shadowy extinctions.
Felspar is present in subidiomorphic grains twinned after the albite and pericline laws.
Tts R.I. is less than that of quartz and greater than that of Canada Balsam. It is
intermediate in composition between oligoclase and andesine and probably is about the
composition Ab,An,. In places it is altered to sericite. Scapolite is present and
contains numerous small inclusions. Sphene and apatite are also present. There are
a few grains of colourless mineral, untwinned and with R.I. less than quartz, and which
may be orthoclase.
P. 355. SCAPOLITE-BEARING PyRoxENE GRANULITE, Erratic (Cape Royds).
Hand-specimen missing.
Under the microscope the fabric is granulitic and the grainsize uneven, the greater
part of the rock having grains of medium size and the remainder coarse. A somewhat
gneissic structure is exhibited. (Plate I, Fig. 4.)
The minerals present are : pyroxene, felspar, quartz, scapolite, sphene, and diallage (?).
Pyroxene is very abundant in medium-sized subidiomorphic grains. It is colourless
and a small amount of absorption is noticeable. It encloses quartz. The felspar is
abundant in fairly large subidiomorphic sections, twinned after the albite law. Sym-
metrical sections give extinctions up to 26°, and therefore it is a labradorite of compo-
BY THE BRITISH ANTARCTIC EXPEDITION, 1907-1909 167
sition Ab,An,. It is fairly fresh and in places has numerous inclusions. Quartz 1s
abundant in rounded, allotriomorphic grains. It shows shadowy extinction but is
not granulated to any extent. Scapolite is fairly abundant in allotriomorphic to subidio-
morphic grains, which are sometimes ragged. It is pretty free from inclusions and in
one or two places exhibits what seem to be traces of albite twinning. Sphene is fairly
abundant and zircon is also present. There are a few grains of a light-coloured mineral
which is probably diallage.
(3) THE BASIC PYROXENE GRANULITES
In this class quartz is either absent or only present in comparatively small amount.
The most basic ones approach fairly closely to a pyroxenite. They contain pyroxene,
felspar, sphene, quartz, apatite, and magnetite. The pyroxene is the same as in the
acid class. The felspar is uniformly labradorite, of composition Ab,An, or very slightly
more basic. Sphene is present throughout and is occasionally very large.
1267. PyroxENE GRANULITE, Erratic (Cape Royds).
The hand-specimen is a mixture of light and dark parts ; the light parts are mostly
quartz veins and the darker ones are made up of felspar and pyroxene. It is fine to
medium grained and shows very little foliation.
Under the microscope the fabric is hypidiomorphic granular, and the grainsize
uneven. Felspar and pyroxene, the two most important minerals, have a tendency to
cluster in bunches, each mineral separately.
The minerals are: felspar, pyroxene, sphene, and apatite.
The felspar is all plagioclase ; it occurs in subidiomorphic grains very variable in
size—some of the grains are as large as 1°5 mm. by 1 mm., while in other places there
is an aggregate of very small felspar grains, which may be due to granulation of larger
felspar grains. It is twinned after the albite and pericline laws, and symmetrical sections
indicate that it is a labradorite with a composition Ab,An,. There 1s very little decom-
position, only a few grains being slightly dusted with decomposition product. A little
sericite is present and may be from the alteration of some of the felspar. The pyroxene
is present as large grains, frequently twinned. It is very light coloured and has uniformly
high extinction angles in longitudinal sections. It is probably diopside but may possibly
be referred to malacolite. Sphene is not abundant but is present in unusually large
sections, reaching such dimensions as 1°5 mm. by 75 mm. Apatite is also present.
1515. PyroxENe GRANULITE, Erratic (Cape Royds).
Hand-specimen very similar to 1267.
Under the microscope the fabric is panallotriomorphic granular ; poikilitic in places by
means of the pyroxene and occasionally by the felspar. A considerable amount of foliation
is shown by the arrangement in bands of the felspar and pyroxene. (Plate I, Fig. 5.)
The minerals are: pyroxene, felspar, quartz, and sphene. The pyroxene is very
abundant in allotriomorphic grains and forms more than half of the rock. _ It is colourless
and ophitically encloses felspar. Felspar is subordinate in amount to the pyroxene
and forms about one-third of the rock. It is twinned after the albite and pericline laws ;
the striations are very fine and give a general appearance of rather coarse microcline.
It poikilitically encloses quartz and more rarely pyroxene. It has the composition
about Ab,An,, obtained by means of symmetrical sections.
Quartz and sphene are sparingly present.
e26. PyYROXENE GRANULITE, Erratic (Cape Royds).
In hand-specimen this is a light-greenish rock, very hard and silicified. Quartz and
pyroxene can be recognised.
Under the microscope this rock varies a good deal in different parts. The section
examined shows quite a contrast between two halves. One-half of the section is a
168 PYROXENE GRANULITES
typical pyroxene granulite with granulitic fabric and small, even grainsize ; it contains
pyroxene and felspar in about equal amounts. The felspar is in small rounded grains,
almost undecomposed and with albite twinning. The larger grains of felspar have,
however, undergone a certain amount of sericitisation. The pyroxene is the same as
has already been described for these rocks. The other half of the section, on the other
hand, approaches very close to a pyroxenite; it is composed almost completely of
rounded, rather small grains of pyroxene. The grains are medium in size and are the
same as the pyroxene in the first-mentioned half of the rock.
P. 216. PyROXENE GRANULITE, ERRATIC (Cape Royds).
Hand-specimen missing.
Under the microscope the fabric is granulitic and the grainsize uneven and fine
to medium.
The minerals are: pyroxene, felspar, quartz, sphene, and magnetite. Pyroxene
is in fairly large grains and is, as usual, colourless ; it forms nearly half the rock. Felspar
is in large allotriomorphic grains, twinned sometimes after the albite law but often
untwinned. It is somewhat decomposed and is a basic labradorite, extinctions in
symmetrical sections going as high as 37°. Quartz is not at all abundant and has
shadowy extinction. Sphene is in numerous small crystals, and magnetite is present.
In conclusion, the writer desires to express his thanks to Professor David and Mr. R. E.
Priestley for the opportunity to do this work and for their kindness and assistance,
and also to Mr. G. J. Burrows for his invaluable help with the analyses.
LITERATURE
For full references up to 1896 see Judd in Phil. Trans., 1896.
1900. CoomAra-SwAmy, A. K. ‘‘ On Ceylon Rocks and Graphite,” Q.J.G.S., lvi, p. 592.
Apams, F. D. Annual Report Geol. Survey, Canada, vii.
1904. Kastner, Max. ““Zur Genesis des sachsischen Granulitgebirges,”’ Centralbl.
Min. Stuttgart, 1904, pp. 196-206.
1903. CoomAra-SwAmy, A. K. Geol. Mag., 1903, pp. 348-850.
Prior, G. T. “ British East Africa,” Min. Mag., 1903, pp. 229-231.
1901-2. Lower, H. J. “The Sequence of the Lizard Rocks,” Trans. R. Geol. Soc.,
Cornwall, 1901 (pp. 488-466) and 1902 (pp. 507-534).
1906. Evans, J. W. “The Rocks of the Cataracts of the Madeira River,” Q.J.G.S.,
1906 (pp. 88-124).
1907. CREDNER, H. “Die Genesis des sachsischen Granulitgebirges,” Centralbl.
Min., 1907 (pp. 513-525).
1907. Pracu, B. N. “Horne, J., ete.,”” Mem. Geol. Surv. Gt. Brit., 1907 (xvii and
668).
1905. | CoomAra-SwaAmy, A. K. ‘“‘ The Rocks and Minerals of Ceylon,” Spolia Zeylan, 3, 1905
(pp- 50-66).
1908. Beret, W. ““Neue Vorkommnisse von Pyroxengranulit und iiber dessen
Allgemeine Verbreitung,” Berlin, Monatsber D. geol. Ges.,
1909 (pp. 231-234).
EXPLANATION OF THE PLATE
Figure 1. Pyroxene Granulite, Erratic, No. 960.
Figure 2. Pyroxene Granulite, Erratic, No. 1537.
Figure 3. Pyroxene Granulite, Erratic, No. 584.
Ficure 4. Pyroxene Granulite, Erratic, P. 355.
Figure 5. Pyroxene Granulite, Erratic, No. 1515.
[Tissue of Plate facing p. 168
wees |
BOL .g ysis stn Yo 9
PLATE I
(To face p. 168
PART XI
PETROLOGICAL NOTES ON SOME OF THE
ERRATICS COLLECTED AT CAPE ROYDS
(With Two Plates and One Figure in the Teat)
BY
Dre. W. G. WOOLNOUGH, D-Sc., F.G.S.
_ Professor of Geology, University of West Australia
566. PEGMATITE
Macroscopic Characters.—Light coloured, somewhat mottled, and slightly
foliated. Texture varies from rather fine to extremely coarse in different parts of the same
specimen, which is evidently part of an aplitic vein in a granite mass. The rock
consists essentially of grey quartz and white felspar. The latter mineral occurs in
crystals up to 40 mm. in diameter, poikilitically enclosing quartz grains. There is
little biotite in flakes up to 5 mm. in diameter.
Microscopic Characters—tThe fabric is allotriomorphic granular, the
average grainsize being about “6 mm.
The minerals are orthoclase, microcline, quartz, oligoclase, and garnet, in order
of abundance.
Orthoclase shows quite considerable strain effects, where these attain a maximum
a decided movrée structure is produced. There is a good deal of granophyric inter-
growth with quartz round the borders of the larger grains. In addition there is
frequently a poikilitic enclosure of quartz grains.
Distinct microcline is present with ‘‘ Gitter-struktur ” well developed, with increasing
fineness of the lamelle a moirée structure is produced so that the microcline and
orthoclase grade insensibly into one another.
Quartz shows very pronounced evidence of strain. In some of the grains this
amounts merely to production of cloudy (undulose) extinction, but many of the grains
are completely shattered.
Oligoclase is subidiomorphic in places though it never has definite crystal boun-
daries. Considerable strain effects are noticeable, including local suppression of albite
twinning, and development of that after the pericline law.
All the felspars are slightly kaolinised; the oligoclase less so, and more locally
than the potash felspars.
Garnet is fairly abundant in small, faintly pmk trapezohedra.
As an accessory mineral a very small amount of greenish mica (bleached biotite)
may be noted. This rock may stand as an example of a very common type amongst
the erratics.
1874. PEGMATITE
Macroscopic Characters.—A medium to coarse grained rock, consisting of
quartz, white felspar, and occasional very large flakes of dark-reddish biotite.
II 169 2A
170 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
Microscopic Characters.—tThe rock is hypidiomorphic granular in fabric
with a medium grainsize. Felspar makes up about 80 per cent. of the minerals
resent,
: Plagioclase about Ab,An,, is present in subidiomorphic sections up to 1 mm. dia-
meter. It shows twinning after the albite Carlsbad and Manebach laws, the striations
being very fine and showing pretty examples of bending. The mineral is somewhat
decomposed, particularly near the periphery.
Orthoclase is untwinned, shghtly decomposed, and exhibits shadowy extinction.
It is moulded on plagioclase, and in some cases there is apparently a crystallographic
relation between the two, the outgrowths of orthoclase showing optical continuity
(Fig. 1).
outs is not very allotriomorphic, and shows shadowy extinction due to strain.
Biotite calls for no special description, it is somewhat frayed and contains inclusions
of apatite.
There is also a very little light-coloured epidote.
Fig. 1. Sketch showing Relation of Plagioclase and Orthoclase. The grains of
orthoclase indicated by X are optically continuous.
439. APLITE
Microscopie Characters.—Allotriomorphic granular rock with an average
grainsize of 0°5 mm., consists essentially of quartz and orthoclase with less abundant
albite and very little decomposed biotite.
Quartz shows slight evidences of strain; orthoclase is quite ordinary. The
plagioclase present is between albite and oligoclase in composition.
Rocks of this type are extremely abundant amongst the erratics; a fact attribu-
table to their resistance to weathering being greater, as a rule, than that of the normal
biotite or hornblende granites with which they were in all probability genetically
connected,
COLLECTED AT CAPE ROYDS 171
438. SyENITE (Plate I, Fig. 1)
Macroscopic Characters.—Dark grey mottled rock, holocrystalline, medium
to coarse. Consists of colourless felspathic material, and still more abundant horn-
blende. The latter mineral is mostly granular but occasionally is in crystals up to
8 mm. by 1°5 mm.
Microscopic Characters—the texture is hypidiomorphic granular with fairly
even grainsize averaging about 1°65 mm. Hornblende and oligoclase-andesine in about
equal proportions make up roughly 80 per cent. of the rock; orthoclase accounts
for about 15 per cent., the remainder being biotite, sphene, apatite, and quartz.
Hornblende is light-greenish in colour, the pleochroism being a =very light greenish-
yellow, {}=bronze-green, ¢=brownish-green, absorption a<>¢c. While the bulk of
the hornblende is no doubt primary, the nuclei of some of the grains suggest
uralite, but no unaltered pyroxene can be observed. Maximum extinction angle
measured in the vertical zone 15°.
Oligoclase-andesine occurs in idiomorphic and subidiomorphic sections twinned
after the Carlsbad, albite, and pericline laws. It is somewhat clouded by decom-
position products, chiefly calcite and sericitic mica. In some instances these products
are zonally arranged.
Orthoclase is allotriomorphic and untwinned. It is somewhat kaolinised but is
less altered on the whole than the plagioclase.
Biotite in bleached flakes is mostly included in the hornblende.
Sphene is present as greyish grains sometimes moulded on the plagioclase.
Apatite im minute, sharply defined prisms is moderately abundant. There is very
little quartz, what there is is graphically intergrown with the orthoclase.
E. 36. Sopa.ire SYENITE witH WO6HLERITE (Plate I, Figs. 2 and 3)
Microscopic Characters—tThis is a most peculiar rock. It is holocrystal-
ne and consists chiefly of felspar, some of the sections of which have diameters of
several millimetres. The larger grains are subidiomorphic. The extinction of this
felspar is cloudy, reminding one of moirée microcline. In some instances excessively
fine crossed twin lamelle can be seen, while in others what looks like perfect microcline
“ grating” is present. The extinction angles of the lamelle are 11° to 13°, but the
refractive index is decidedly higher than that of cooked Canada balsam, so that the
felspar cannot be microcline, and must be a plagioclase near andesine, with quite
abnormal development of twin lamellz. The values for extinction angles given
above are not at all satisfactory as the extinction is very cloudy.
The grains of felspar are crowded with markings like those producing “ schiller ”
structure in hypersthene. These are really plates of an isotropic substance perfectly
colourless and with a refractive index much below that of Canada balsam, and which
I believe to be sodalite. This regular intergrowth of felspar and sodalite forms a
veritable sodalite microperthite. In sections cut at right angles to the plane of the
plates of sodalite the structure appears laminated. In addition to this intergrowth
other felspars without twinning, but with the same relatively high refractive index,
show perthitic intergrowth with the microcline-like felspar above described.
Scattered through the rock, and included in the felspars, are fairly abundant stout
prisms up to1*2 mm. by 0°3 mm. of a bright orange-coloured mineral. This has a positive
elongation and gives extinctions up to 32° from the length. There is a decided cleavage
parallel to the length. The refractive index is considerable and birefringence strong.
172 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
It is biaxial, optically positive, with 2V fairly large and shows very decided dispersion,
p<.
These characteristics are somewhat puzzling. At first sight the mineral suggests
a member of the epidote group, but the constant high extinction measured from the
length and the character of the dispersion seem to put epidote out of court.
Of a!l the minerals described in Rosenbusch’s Mikroskopische Physiographe wohlerite
possesses most features in common with the one under discussion.
It is quite possible that we are dealing with a new mineral; but, unfortunately,
only a very small chip of the rock was collected, and there was not sufficient material
for analysis or for mineral separation.
Another feature of this remarkable rock is the habit of the magnetite, which is a
fairly abundant constituent. In addition to normal octahedra there are still more
abundant distorted crystals possessing a prismatic habit.
Magnetite and wohlerite occur together, forming intergrowths.
Apatite is present in exceptionally large crystals up to 1 mm. by 0:2 mm., together
with interstitial sodalite and small grains of magnetite and wohlerite. Here and there
quite large patches of sodalite occur.
535. SoDALITE SYENITE
Macroscopic Characters.—Light grey rock of even grainsize (05 mm.)
composed essentially of felspathic and ferromagnesian minerals in about equal propor-
tions. The ferromagnesian minerals include black augite and dark-reddish mica.
Microscopic Characters.—Hypidiomorphic granular rock of medium grain
consisting essentially of anorthoclase sodalite, augite, olivine, biotite, micaceous
hematite, and magnetite; with smaller quantities of hornblende, oligoclase, and
apatite.
Anorthoclase is much the most abundant constituent; it is subidiomorphic and
tabular parallel to (010). Twinning on a large scale is after the Carlsbad law or is
absent, but the individuals are always multiple twinned on an extremely fine scale
so that the extinction is quite cloudy. Only occasionally can the actual twin lamellee
be resolved. The refractive index is never higher than that of Canada balsam and is
mostly decidedly less.
Sodalite is not very abundant. It is mostly interstitial but in some instances
appears to be perthitically intergrown with anorthoclase.
Augite, light bluish-grey, subidiomorphic and mostly untwinned. The crystals
are crowded with inclusions chiefly of apatite and magnetite. The mineral is not
pleochroic. 2V is large. The grains are moulded on olivine, but are older than horn-
blende and biotite.
Olivine in idiomorphic crystals up to 0°63 mm. by 0:28 mm. is decidedly yellowish
in colour and considerably altered around the outside and along cracks with separation
of much magnetite. Two of the cleavages are quite perfect. Double refraction is
very strong, while the optic axial angle, though quite large, is nevertheless relatively
small for olivine.
Biotite in irregular flakes and occasional subidiomorphic sections, averaging about
22 mm. diameter, is very dark in colour, the pleochroism being from brownish-red
opaque. It is crowded with plates of micaceous hematite lying parallel with the
cleavage.
Micaceous hematite is very abundant in flakes averaging 0°16 mm. diameter.
Hornblende is not abundant; it occurs mostly associated with augite, forming
a halo round that mineral. The colour is very dark brown, and, when the trace
COLLECTED AT CAPE ROYDS 173
of the vertical axis is parallel to the plane of vibration of the polarizer, it becomes
opaque. ; ;
A few small but sharply defined crystals of oligoclase are included in the anortho-
clase.
A noteworthy feature is the very considerable abundance of sharply prismatic
apatite.
This rock is a most peculiar type. In mineral composition it is like laurdalite,
except that sodalite is substituted for nepheline. There does not appear to be any
alteration product present which would have been formed from nepheline.
443. QUARTZ-DIORITE (Plate I, Fig. 4)
Macroscopic Characters.—A most strikingly handsome rock type. It is fairly
coarsely crystalline and is mottled black and white. Sharply idiomorphic prisms
of lustrous hornblende up to 10 mm. by 2 mm. are scattered very abundantly through
a base of the lighter coloured constituents. Less abundant but quite as conspicuous
are very large plates of biotite 18 mm. in diameter, more or less chloritised. Yellowish
orthoclase occurs in pseudo-porphyritic grains up to 20 mm. diameter, contaiming
very abundant inclusions of hornblende, biotite, and idiomorphic, colourless
plagioclase.
In the light-coloured interstitial material orthoclase, plagioclase, and not very
abundant quartz can be recognised.
A very remarkable feature of the rock is the habit and abundance of apatite, which
occurs in yellowish and colourless needles up to 8 mm. long by 0°2 mm. thick.
Microscopic Characters.—The texture of the rock is holocrystalline
porphyritic with hypidiomorphic granular base of medium grain.
Under the microscope the most conspicuous and abundant minerals are the felspars,
of which there is a considerable variety.
Orthoclase composes the largest grains in the rock. In addition, there are smaller
grains and patches of the same mineral scattered through the slide. The grains are
all completely allotriomorphic, the larger ones poikilitically enclosing crystals of most
of the other minerals. Towards quartz the mineral shows occasional traces of crystalline
outline, but often the two minerals are intergrown. It is slightly clouded by decom-
position, and shows veins due to perthitic intergrowth. All the sections are
untwinned.
Plagioclase exists in at least two habits, corresponding to two different varieties :
(a) strongly idiomorphic thick tabular crystals, twmned after the albite and pericline
laws, and often after the Carlsbad law as well; (b) in subidiomorphic to allotriomorphic
grains with Carlsbad and albite twinning. In the former case there are strongly
marked zonal effects which are perfectly continuous from periphery to centre.
Those of the first set are frequently included in individuals of the other type. In
the central portions of the former the symmetrical extinctions of the albite lamelle
give a maximum of 32°, with a difference (4) of 21° for the extinction in the other
half of the Carlsbad twin. The peripheral portions give perfectly straight extinctions.
Hence the variation is from Ab,An, on the outside to Ab,An,, at the centre.
The felspars of the second period are less strongly zoned than those of the first,
though still quite a noticeable “‘ undulation” in the extinction occurs. The angles
measured point to Ab,An, as the composition of the interior while the periphery is
more acid.
All these felspars are irregularly clouded by decomposition products (chiefly very
fine grains of calcite) and are dusted round their edges with similar material. This
174 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
makes comparison of refractive indices difficult. In most instances the refractive
index of the plagioclase is greater than that of Canada balsam, but an occasional section
of the peripheral portion of a crystal of the first period exhibits equality of refractive
index with the same standard. ‘The refractive index of the peripheral zones of felspars
of the first period is very decidedly less than that of the grains of the second period
in which they are imbedded. Quartz is moderately abundant in large grains mostly
strained, and many of them showing signs of incipient granulation. Very abundant
fluid cavities with spontaneously moving bubbles are present.
Hornblende is abundant in idiomorphic prisms. It is notably complex in character,
showing a decided zoning, the central portion being dark brown and the peripheral
part dark green. The pleochroism of the brown portion is:
= bright golden yellow ;
O = very dark brown;
= dark greenish-brown.
Sections parallel to (010) show twinning, and yield symmetrical extinctions of 17°.
The passage from brown nucleus to green rim is very gradual. The central portion
frequently shows no cleavage, but is strongly schillerised.
Biotite is fairly abundant in subidiomorphic sections. The pleochroism is golden
yellow to dark reddish-brown. The crystals contain inclusions of apatite, plagioclase,
and zircon (the latter with pleochroic halos).
Biotite and hornblende frequently show regular intergrowths with definite morpho-
logical relationship. Sometimes one is inside, sometimes the other, but mostly the
hornblende is the older. Frequently the biotite is completely altered into dark green
penninite.
Apatite is extremely abundant in perfect crystals.
448, GRANOPHYRIC GRANITE-PORPHYRY
Macroscopic Characters.—Grey mottled with dark and light spots. The
groundmass is fairly fine in grain and consists of felspar and biotite. The lighter
coloured phenocrysts consist of pink orthoclase (3 mm.) and grey plagioclase (8 mm. by
3mm.). The dark patches are finely granular aggregates of greenish-black colour
up to4 mm. by 2 mm.
Microscopic Characters.—the fabric of the base is panidiomorphic granular
with the exception of fairly abundant patches which are distinctly granophyric.
The base consists of felspar, quartz, and biotite, with a little accessory zircon
and magnetite. The felspars of the base are idiomorphic and subidiomorphic and
very even in size. Mostly they are untwinned, have a refractive index less than
that of Canada balsam, and give very nearly straight extinctions, so that they are
probably orthoclase. A few appear to possess very hazy albite twinning and may
possibly be anorthoclase. These felspars are considerably kaolinised so that satis-
factory determinations are difficult.
Quartz is not so abundant as felspar; some of it is idiomorphic, some enters into
beautiful granophyric intergrowth with the felspar.
The ferromagnesian constituent is not abundant. It occurs in small flakes whose
pleochroism is from yellow to dark brown. From this condition it is present in various
stages of bleaching, the ultimate product being an aggregate of green fibres. While
these aggregates have been described as an alteration of biotite it 1s possible that they
COLLECTED AT CAPE ROYDS 175
consist of dark uralite with a very small extinction angle. The only conspicuous
phenocrysts are felspar much kaolinized and affording no very satisfactory measurements.
Some appear to be orthoclase untwinned or twinned after the Carlsbad law. Others
are certainly plagioclase with Carlsbad, albite, and pericline twinnings; the measure-
ments indicate very acid oligoclase. In addition there is a good deal of hazy perthitic
intergrowth of the felspars and also fringes of granophyre round the felspar grains.
Chemical Composition.—The following is an analysis of this rock by
Messrs. Burrows, B.Sc., and A. B. Walkom, B.Sc. :
Sire CE Aaa ceo 6800
Ti0, : : ; : : i 0:16
Al,O5 , : i : : : 17 28
KeO : : : ‘ : 0:07
FeO : ‘ ‘ ; . : 3°56
MgO : : 5 : ‘ ‘ 0°37
CaO : : : : . , 1°67
KA Ore arene ee: OER) i ay 3°59
Nac Ope ee ae re eth tals 4 5 4:08
EO are eed Ws we Cpa he 0°46
HOS: : ‘ ; : < 0:23
CO, . : : : : ; 0°27
MnO : : : C : : 0°05
P.O; : : : : : : Trace
99°79
447, GRANOPHYRE
Macroscopic Characters.—F¥ine-grained purplish-pmk rock, of very even
grainsize with a few larger black grains of biotite scattered through it, and occasional
phenocrysts of pinkish felspar 2mm. by 1 mm.
Microscopic Characters.—Somewhat porphyritic rock with even-grained,
holocrystalline base, the average grainsize being about ‘35 mm.
The fabric is micro-graphic. The chief constituents are quartz, felspar, and biotite
with minor constituents. There are idiomorphic-phenocrysts of felspar. These are
mostly untwinned, but some show Carlsbad twinning, and some lamell after albite
and pericline laws. No satisfactory extinctions were obtained, but an examination
of relative refractive indices indicates that the felspar is oligoclase. All the grains are
somewhat decomposed and are surrounded by secondary outgrowths of orthoclase
identical in character with the felspar of the groundmass, and, like it, subject to grano-
phyric intergrowth with quartz.
The orthoclase of the groundmass is in quite irregular grain; sometimes these are
solid throughout, sometimes solid at the centre with a fringe of granophyric structure
round the edges, or granophyric throughout, or, lastly, there may be a quartz nucleus
with a granophyric fringe, but this is rarer. The felspar throughout is somewhat
clouded by decomposition products.
Quartz is mostly interstitial, though, as above noted, it sometimes forms the nucleus
of a granophyric intergrowth.
Biotite occurs in very ragged flakes up to 1 mm. by 0°2 mm. It is all somewhat
altered so that the pleochroism is from dark greenish-yellow to opaque. Some flakes
176 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
are decidedly green, others are clouded and opaque through deposition of limonite.
A very little magnetite and apatite are present, and a few small grains of fluorite.
The order of crystallization is somewhat peculiar in this rock: of the essential
minerals biotite certainly began to form first, but continued to form for a long time,
as it is moulded on all the other minerals, including even quartz. The oligoclase
crystals ceased to form comparatively early.
613. Frtspar PorPHYRY
Microscopic Characters.—tThe phenocrysts appear to include two species of
felspar both occurring in idiomorphic crystals.
Some of these are completely clouded so that measurements are not possible; they
appear to be orthoclase. The others are mostly clear, but are decomposed in patches
and sometimes zonally. They exhibit well-defined Manebach twinning as well as
that after the Carlsbad and albite types. They are mostly slightly more acid
than Ab; Ani, but in some instances there appears to be a definite intergrowth with
oligoclase in discontinuous strips parallel to the trace of the vertical crystallographic
axis.
The base is finely panidiomorphic granular. It consists chiefly of untwinned
columnar felspar, with square cross-sections. The extinction of these laths is never
more than 8° from their long axes, so that the felspar is probably soda-orthoclase.
In many instances such prisms have a “core” formed by a flake of biotite.
Round many of them there is a fringe or halo of very fine granophyric intergrowth
with quartz. These felspars are a little decomposed. There is a small amount of
free quartz, both interstitial and in subidiomorphic grains, and also a fair amount
of biotite in thin, bent flakes with greenish-yellow to dark green pleochroism. Minor
constituents are magnetite, sphene, and calcite-epidote aggregates representing the
alteration products of a pyroxene or amphibole.
7. Mtnerte (Plate I, Fig. 6)
Minette (approaching Camptonite) with a xenolith of altered quartzite. _
Microscopic Characters.—The minette is a fine-grained panidiomorphic
granular rock without porphyritic structure, composed essentially of prismatic horn-
blende, plates of biotite, interstitial orthoclase, a little epidote and sphene, and very
little ilmenite.
Hornblende is in sharply idiomorphic prisms 0‘1 mm. by 0°01 mm.; cross-
sections are bounded by (110) with or without (100), but with no trace of (010).
Pleochroism is slight, a colourless, { and ¢ faint green, extinction angle 15°.
Biotite is in thick hexagonal plates, ‘06 mm. in diameter; strongly idiomorphic.
These are pleochroic from light brown to dark brown.
Away from the contact there is no augite.
The felspar, whose refractive index is less than that of Canada balsam, forms a not
very abundant paste. ?
On the other side of the contact the rock consists essentially of quartz and augite
(with, possibly, some epidote). The quartz amounts to about 40 per cent of the rock.
It is in fair-sized grains, showing considerable undulose extinction. The augite is
finely granular and colourless.
The contact zone, which is about 2 mm. in width, is rather finer in grain than the
rock on either side. On the minette side there is an admixture of augite in fine grains,
COLLECTED AT CAPE ROYDS 177
and a very well-marked development of “ Schlieren.” On the quartzite side there is
a noticeable development of biotite and a little hornblende.
The altered rock is probably derived from an argillaceous sandstone rather than
from an eruptive rock, as no felspar is present in it.
534. MINEerTEe
Macroscopic Characters.—Dark grey granular rock with occasional irregular
light-coloured patches. The apparent grainsize isabout 0°25 mm. The most abundant
constituent is a greenish-black micaceous mineral. Interstitial felspar is not abundant.
The larger white patches are of quartz and calcite up to 3 mm. in diameter.
Microscopic Characters.—Grainsize even, fabric panidiomorphic granular.
The most abundant constituent is orthoclase in idiomorphic crystals, untwinned or
twinned after the Carlsbad law. Occasionally a multiple-twinned plagioclase crystal
can be seen whose extinction angles and refractive index point to a composition of
Ab,An, about.
All these felspars are very much clouded by decomposition, and are crowded with
flakes and tufts of light-yellowish chlorite or mica. Many such clouded crystals have
outgrowths of clear orthoclase in crystal continuity. In both nucleus and outgrowth
the extinction angles, measured from the long axis, are very small; but a difference
of 1° or 2° between inner and outer portions can be detected. Many of the cloudy
crystals are enclosed in extensive optically continuous areas of somewhat cloudy
orthoclase.
Some of the felspars are more or less replaced by quartz in a manner so irregular
as to point to metasomatic action.
There is much biotite with very light yellow to reddish-brown pleochroism, and
showing bright polarisation tints. This mineral is considerably altered to green
penninite with separation of the titanium content in the form of “ sagenite” webs
and granular leucoxene. Much ilmenite is present, slightly decomposed to leucoxene.
Apatite in relatively large needles is very plentiful, but is almost confined to the
quartz, and does not enter much into the felspar or biotite.
There is not much calcite, but what there is is in large patches mixed with quartz
in such a way as to suggest progressive replacement by the latter mimeral.
There is quite abundant clear quartz, mostly interstitial in character, and probably
secondary. The graphic intergrowth with what appears to be secondary orthoclase
has been noted above, as has also the fact that the quartz contains inclusions of apatite.
The appearance is strongly suggestive of secondary action having introduced quartz,
orthoclase, and apatite. Such a process, if it happened, is somewhat remarkable.
1066. VOGESITE
Macroscopic Character s.—Dark-greenish rock of very fine grain. The only
noticeable feature is the development of abundant irregular flecks of dark-coloured
material up to 2 mm. diameter.
Microscopic Characters.—tThe rock, which is much decomposed, shows a
holocrystalline porphyritic structure with a panidiomorphic granular base. It is com-
posed essentially of felspar, hornblende, uralitised augite, and chlorite (apparently after
biotite), in about equal proportions. The felspars average about 0°25 mm. by 0:1 mm.
in size, and are very cloudy from secondary material. All are apparently ortho-
clase.
II 2B
178 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
Hornblende is in idiomorphic prisms with an extinction angle of 17° on (010) :
a = yellow; 6 = dark brown; ¢ = dark brown.
a<<b>c
The sections are somewhat chloritised. The mineral occurs in one generation
only.
guint occurs in small flakes and also in large patches (penninite). These large
patches are all apparently in secondary spaces, and are associated with other secondary
minerals. The smaller flakes suggest original biotite, but none of the latter mineral
has survived.
Augite occurs in two generations. The individuals belonging to the second are
about equal in size to those of felspar and hornblende. They occur in quite colourless
prisms with extinction angles up to 45°. Sometimes the ends of the prisms are frayed
out and uralitised ; the central portions are fresh. In many instances they have been
converted into green reedy hornblende, quite distinct from the primary mineral. The
augites of the first generation are in grains up to 0°5 mm. by 0°3 mm., colourless and
with 2V very large. There is much epidote (pistacite) in relatively coarse-grained
aggregates up to 1 mm. in diameter, associated with calcite, uralite (in fibres), penninite
and a biaxial zeolite, apparently stilbite. No fresh iron ores are present, but there is
much leucoxene.
372 (P. 112). Porpuyrite (Plate I, Fig. 5)
Macroscopic Characters.—Mottled rock with dark grey lithoidal base. The
phenocrysts are white plagioclase up to 10 mm. by 4 mm. (but mostly much smaller),
sharply defined hornblende prisms up to 4mm. by 1 mm., and biotite up to 2 mm. by
1 mm.
Microscopic Characters—tThe rock is porphyritic with a panidiomorphic
granular base, whose average grainage is about 0°04 mm. ‘The base consists chiefly
of acid felspar (probably anorthoclase), with small quantities of quartz, and
flakes of green and brownish minerals, including apparently both hornblende and
biotite.
The most abundant phenocrysts are plagioclase in thick tabular crystals, giving
sections up to3 mm. by 1 mm. These are zoned, and measurements indicate a com-
position of Ab,An, for the outer zones, while the bulk of each crystal is shghtly more
basic than Ab,An,. These felspars are very slightly decomposed and contain liquid
inclusions with moving bubbles.
Hornblende is present with prismatic habit, sharply idiomorphic and characterised
by a strong development of the orthopinacoid (100). The highest extinction in sections
from the prism zone is 15° measured from the trace of the vertical axis. The pleo-
chroism is:
a = hght yellowish-green ;
6 = dark clove-brown for the inner portions;
b = very dark brownish-green for the outer zone;
¢ = very dark green, almost opaque.
Absorption = a<f<e.
This zoning is not prominent in vertical sections, but is well marked in those which
are cut transversely. The characters of this hornblende suggest a relationship between
this rock and numbers 441 (p. 180) and 452 (p. 179). The present rock may represent
COLLECTED AT CAPE ROYDS 179
a hypabyssal facies of which the other two are the plutonic and volcanic types
respectively.
Biotite is idiomorphic to subidiomorphic in sections up to 1°2 mm. by 05 mm.
It shows pleochroism from golden yellow to very dark brown, some basal sections
being practically opaque.
Apatite and zircon occur as inclusions in both hornblende and biotite.
There appears to be considerable overlap in the crystallisation periods of the
porphyritic constituents. Hornblende is for the most part the earliest, but very
occasionally is moulded on felspar and hornblende; but also occurs included in the
large felspars.
284 (610). SericiTisED D1iABAse-PoRPHYRY
Microscopic Characters—the base of the rock is rather coarsely pilotaxitic
in fabric. It consists mostly of oligoclase-andesine in idiomorphic crystals, 0°3 mm.
by 0°2 mm., which are fairly fresh and undecomposed. There is a good deal of strongly
prismatic uralite in crystals, 1 mm. by 071 mm., a little dark brown biotite in flakes
or confused aggregates, and still smaller quantities of magnetite. Throughout the
base abundant leucoxene is scattered.
The phenocrysts are large idiomorphic plagioclases up to 15 mm. by 0°5 mm.,
almost completely sericitised. In the majority of instances the phenocrysts are con-
verted into pseudomorphs of interlacing fibres, the whole aggregate possessing strong
double refraction; but there is always an outer zone of clear felspar, showing strongly
zonal extinction, but with low angles like those of the felspars of the second generation.
In a few instances patches of the original material are sufficiently unaltered to get
symmetrical extinctions up to about 32°(Ab,An,,). Under high powers the alteration
products of the felspar can be resolved into fine interlacing laths of sericitic mica
extending inwards from the sides of the original crystals. While there may be con-
siderable divergence of individual laths yet there is a very marked regularity in their
general arrangement. They are distributed along certain definite crystal planes whose
positions have not been identified. In any particular haphazard section the angles
between the different solution planes (if such they be) depends upon the orientation
of the section. In one instance, where two well-defined axes of arrangement made
an angle of 58° with one another, the traces of the (001) and (010) cleavages of the
felspar appeared symmetrically placed with respect to the said axes. This rather
suggests that a pair of brachydome faces may lie parallel to the solution planes, but
of this I cannot feel at all certain.
There is a good deal of secondary material throughout the rock. Leucoxene has
been mentioned already. In addition there is much quartz, calcite, and some chlorite.
The quartz and calcite often enclose or partly enclose the main constituents of the rock,
suggesting an original miarolitic texture.
452. SOLVSBERGITE (Plate II, Figs. 3 and 4)
Macroscopic Characters.—Dark grey porphyritic rock with stony ground-
mass. There are abundant phenocrysts of colourless felspar, up to2 mm. in diameter occa-
sionally. Hornblende is very abundant and conspicuous in sharply defined prisms
which occasionally reach 5 mm. by 0°5 mm., but are mostly much smaller. Occasional
grains of pyrites are visible.
Microscopic Characters.—tThe rock is porphyritic, with very fine textured
pilotaxitic base consisting of lath-shaped felspars apparently hornblende and quartz
granules,
180 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
The most abundant phenocrysts are plagioclase, twinned after both Carlsbad and
albite laws. There seem to be two sets of phenocrysts of plagioclase, the larger ones
are andesine Ab,An, on the outside and approach anorthite in the kernel and are
very strongly zoned, These have dimensions about 1°5 mm. by 0°75 mm., parallel
to (010), but are very thin, only about 0°15 mm. in the direction of the b axis.
The other plagioclase phenocrysts are smaller and stouter than these, and are more
acid in character.
The most striking mineral present is the amphibole, which is markedly composite.
The greater part of each crystal is brown in colour, but the outer zones, and particularly
the ends of sections from the prismatic zone, are dark green. In a section parallel to
(010) c:¢ = 14°. The pleochroism is:
a = brownish-yellow ;
6 = reddish-brown;
c = dark clove-brown ;
and absorption a< b= c.
These properties indicate that the mineral is barkevicite.
The optical properties of the green portion are somewhat anomalous, and perfect
extinction between crossed nicols does not occur. The extinction angle appears to be
about 5° greater for the green than for the brown. Many of the crystals are twinned
after the common law, and, in addition, some curious interpenetration twins occur also.
Quartz is not abundant, the grains average about 0°25 mm. in diameter, and are
granophyrically intergrown with orthoclase round the borders. In addition to the
orthoclase just mentioned there are a few independent crystals, twinned after the
Carlsbad law, and perfectly clear and undecomposed.
A few apatite needles are scattered through the rock.
Flakes of green penninite occur, indicating that biotite was an original constituent
of the rock in all probability.
441. SOLVSBERGITE
Microscopic Characters.—Somewhat similar to No. 452 but less trachytic
in structure. The base consists of a confused aggregate of rather decomposed, un-
twinned orthoclase, abundant greenish chloritic material (probably derived from
amphibole) and very little quartz.
The phenocrysts are kaolinised felspars with zonal decomposition near periphery.
The refractive index of these is less than that of quartz but equal to or greater than
that of Canada balsam. Some of them show multiple twinning but no good sections
for determination were encountered.
A few grains of quartz which are present seem to be foreign inclusions. One fragment
included in the slide consists of quartz, complicated saussuritised felspar, a very large
apatite crystal and green hornblende quite distinct from that of the rock itself.
Hornblende is abundant in perfectly idiomorphic crystals very similar to that in
No. 452, but without the well-marked green borders there described.
430. SAPPHIRE-BEARING TRACHYTE
Microscopic Characters.—the rock is markedly trachytic in character, with
a few porphyritic crystals.
The base consists mostly of lath-shaped felspars up to1‘2 mm. by 0°04 mm. Almost
all are sharply twinned on the Carlsbad law, and one or two of the largest show hazy
patches of what may be very fine multiple twinning, but this is doubtful. One of the
COLLECTED AT CAPE ROYDS 181
larger twinned microlites shows symmetrical estimations of 8° and the smaller ones
give extinctions from 0° up to 8°, so that they consist of soda-sanidine. Many of them
are forked and bent. The larger crystals are crowded with apatite and magnetite
inclusions, the latter being zonally arranged.
There is a good deal of interstitial augite of a green colour often ophitically enclosing
the felspar laths. In some cases the augite grains are covered with a network of black
needles strongly suggesting skeleton crystals of magnetite.
The infrequent phenocrysts consist of tabular felspar with undulose extinction, augite
with an extinction angle of 41°, and large corroded grains of brown sphene,
One small grain of light blue sapphire occurs in the slide.
387 (E. 11). CoRUNDUM-BEARING TRACHYTE (Plate II, Figs. 1 and 2)
Microscopic Characters.—Porphyritic, with trachytic base.
The base is composed of sanidine needles, augite needles, magnetite, and a little
glass. There is a very strong fluidal arrangement of the constituents. Sanidine in
crystals 5 mm. long and very narrow shows Carlsbad twinning only. The extinction
nowhere measures more than 3° from the length of the needles.
Augite is hght green, much corroded, and of the same order of size as the sanidine.
Magnetite. Idiomorphic sections very minute but pretty numerous.
Phenocrysts are numerous.
Plagioclase in sections up to 4°5 mm. by 0°9 mm. with symmetrical extinction of
the albite lamelle of 8°, and a refractive index decidedly higher than that of Canada
balsam. The plagioclase contains very remarkable inclusions. There are small apatite
crystals and grains of greenish augite and of almost opaque dark hornblende; these
are not abundant. There are, however, large irregular patches and inclusions in the
form of negative crystals of colourless glass. From the edges of some of the larger
cavities partial spherulites composed of slightly greenish fibres extend inwards.
There are a few large phenocrysts of anorthoclase up to2 mm. by 0°8 mm. of sanidine-
hke habit. These show Carlsbad twinning, and very occasional small patches of gridiron
twinning. The extinction angles are almost straight and the refractive index is about
equal to that of Canada balsam. The optical sign is negative and the optic axial angle
small. The mineral is perfectly fresh and is probably anorthoclase. The most con-
spicuous constituents of the rock are numerous, almost completely altered crystals
of dark hornblende up to 1 mm. by 05 mm. The resorption has completely darkened
the sections in most instances, but here and there small elliptical patches of the original
mineral are preserved. The colour is brown and there is strong pleochroism, brownish-
yellow when the vibrations are transverse, brownish-orange when they are longitudinal
In prismatic sections. In every grain examined the extinction angle was very small,
not more than 2°. Some of the sections are distinctly twinned, the extinction being
just sufficiently oblique to make the phenomenon apparent. The perfection of cleavage,
the colour, the double refraction, and the very small extinction angle all suggest biotite ;
but the optic axial angle is very considerable, hence I have called the mineral horn-
blende. It is possible that both minerals may be represented. Each, very much altered,
crystal is surrounded by a halo of small augite needles and grains in the base.
There is a little bright red micaceous hzmatite.
Augite m purplish phenocrysts, stout prisms 0°25 mm. long, is easily confused with
the corundum on casual inspection.
a = brownish-grey ; 0 = grey-violet ;
C = purple; 2V is large.
182 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
Corundum in the form of sapphire is quite a notable constituent. It occurs in
tabular crystals, 0°1 mm. by 0°02 mm., very much corroded by the magma. It is not
noticeably pleochroic. It is included in all the other minerals except apatite, of which
there is a little.
There are irregular glassy veins about 0°05 mm. in width running through the rock.
Sanidine crystals project from the sides, suggesting a miarolitic fabric. Here and there
are tufts of fibrous radial mineral like that described in the inclusions in the felspar.
The interstices are filled with colourless glass (or possibly opal).
444. SpHERULITIC TRACHYTE
Macroscopic Characters.—Very fine-grained rock of brownish-grey colour,
with rather scanty phenocrysts of felspar up to 3 mm. by 1 mm.,, and still less
abundant thin flakes of biotite up to 5 mm. by 1 mm.
Microscopic Characters.tContais phenocrysts of felspar, biotite, and
magnetite in a finely spherulitic base.
The base consists mostly of microlites of felspar and biotite with a little interstitial
quartz, and felspar of a character different from that of the microlites. This interstitial
felspar is certainly orthoclase.
The microlites have rather a rosette grouping than a spherulitic arrangement.
Many of the microlites are distinctly cored.
The main part of the crystal extinguishes at 53° from the length, while the core
extinguishes at 22°. The highest extinctions measured in such microlites is 12°, and
the elongation is negative.
Quartz and biotite are not abundant; the former shows very fine granophyric
structure in places.
The phenocrysts of felspar are most remarkable in exhibiting a veritable “ bearded ”
structure. The main crystals are strongly idiomorphic and apparently consist of anortho-
clase and plagioclase. Rather unsatisfactory measurements indicate a normal andesine
for the latter, which show complicated twinning after pericline, albite, Carlsbad, and
Manebach laws.
While any of the porphyritic felspars may show the remarkable outgrowths above
mentioned they are much more frequent and striking on the anorthoclase.
Along the direction of the brachy-diagonal the microlites are closely set and parallel
to the crystal axis, but on other faces and on fracture they tend to arrange them-
selves in rosettes. In character they are similar to the microlites of the base except
that none were noticed showing the forked structure described above. The extinction
angle is 14° from the length of the fibres.
Biotite phenocrysts are not very abundant and are mostly associated with pheno-
crysts of felspar or included in masses of the latter. This rather suggests that some
of the larger felspar crystals, together with these aggregates, may be included fragments
of older rocks. The biotite shows light yellow to very dark reddish-brown pleochroic
colours, and is crowded with apatite crystals and contains also a few minute zircons
with pleochroic halos. Side by side with perfectly fresh crystals of biotite occur others
of similar size and habit completely converted into bright green penninite.
433. DrnsE Porpuyritic BASALT
Microscopic Characters—tThe base is a very dense aggregate of minute
brown needles of augite and tiny octahedra of magnetite with somewhat larger
microlites of plagioclase whose composition is about Ab,An,.
COLLECTED AT CAPE ROYDS 183
The phenocrysts are chiefly purplish titaniferous augite whose size is about 0°56 mm.
by 0°34 mm. These are slightly pleochroic, have an extinction angle on (010) of 41°
from the cleavage, birefringence notably weak for an augite, and a wide optic axial
angle.
Rice of labradorite up to 7°0 mm. by 2°5 mm. also occur. These have
a composition about the same as those of the base and exhibit Carlsbad and albite
twinning. One very noticeable feature is the great abundance in them of corrosion
hollows or inclusions of brownish glass, a characteristic which appears to be common
in rock types intermediate in mineral composition and texture between basalt and
andesite.
Large crystals of olivine (1'7 mm. by 0°8 mm.) occur. The cleavage is very good for
olivine, and the optic axial is almost 90°.
1278. ACTINOLITE GNEISS (Plate II, Fig. 6)
Macroscopic Characters.—Medium-grained, strongly foliated rock, the colour
bands of which are about25 mm. wide. The lighter coloured bands consist of quartz and
white felspar, the darker ones of these minerals together with an equal amount of light
green actinolite in roughly prismatic grains.
Microscopic Characters.—the rock is porphyroblastic with a granoblastic
ground fabric. Quartz is the most abundant constituent. In the large, complex grains
and in the ground fabric also it shows considerable evidence of strain. The large grains
are almost certainly secondary growths. There is a good deal of another colourless
mineral whose refractive index is greater than that of the quartz; this is most likely
untwinned plagioclase. An occasional grain shows exceedingly fine lamellar twinning
through part of it. Still more colourless material has a refractive index less than that
of quartz, and is probably orthoclase. There are occasional phenocrysts of andesine
up to2 mm. by 1 mm. Actinolite is in irregular patches up to 1 mm. by 0°5 mm.
showing sieve-structure. On rotation it changes from faint green to colourless.
There is a little sagenite.
A good deal of colourless epidote is present in prisms and aggregates, generally
associated with the actinolite.
440. TREMOLITE GNEIss (Plate II, Fig. 5)
Macroscopic Characters,—Grey schistose rock, medium grained, somewhat
foliated. On fresh fractures the lustre is almost silky owing to the flashing cleavage
faces of the very fine tremolite prisms in parallel orientation.
Microscopic Characters.—Granoblastic, with a decided tendency to lepido-
blastic texture in places. Average grainsize 15 mm.
Untwinned and multiple-twinned felspar and tremolite are the most abundant
constituents, though the amount of quartz is notable.
Felspars showing albite twinning give symmetrical extinctions up to 23°, indicating
labradorite of the composition Ab,,An,. These felspars are very slightly sericitised.
There is also a very little untwinned orthoclase. Tremolite is in well-defined rods
which are almost colourless, and show, at most, a very faint brownish-grey tint when
the vibrations are parallel to the axis of greatest absorption, namely, ¢.
Quartz is in irregular grains with well-marked undulose extinction due to strain.
Small irregular grains of sphene and crystals of apatite and pyrites are rare.
184 PETROLOGICAL NOTES ON SOME OF THE ERRATICS
1863. ACTINOLITE ScHIST
Macroscopic Characters.—Very dense grey rock with decided tendency to
cleavage. Transverse to the direction of parting a perfect conchoidal fracture is
developed. An obscure banding can be noticed. No individual constituents can be
recognised.
Microscopic Characters.—The banding noted in the hand-specimen is very
distinct under the microscope. The more coarsely crystalline bands are extremely fine,
and the finer ones are crypto-crystalline. The coarser bands have strongly parallel
arrangement of the prismatic constituents. Most abundant and conspicuous are
prisms of actinolite up to 0°2 mm. long and extremely slender. These, together with
flakes of light brown mica and longish splinters of quartz, are embedded in a base of
quartz and twinned and untwinned felspar, too fine for optical determination.
In the finer bands actinolite prisms of much larger size (0°8 mm. to 0°2 mm.) are
sparsely distributed. In cross-sections of these prisms the trace of the (100) face is
predominant and (010) is absent. Sometimes these larger prisms project from the finer
into the coarser bands. In the latter the centres of crystallization of the amphibole are
much more numerous, and there is a tendency for the formation of feathery aggregates.
It is possible that this rock is a somewhat altered lightish coloured lamprophyre
of very fine grain. The arrangement of the larger actinolite crystals is a little suggestive
of this; but, on the other hand, the habit of this mineral, the character of the mica, and
the mode of occurrence of the quartz all point to a metamorphic origin. The rock
is very similar to quite a number of others whose metamorphic origin 1s undoubted.
1869. ACTINOLITE SCHIST
Macroscopic Characters.—Very dense and heavy dark-greenish rock, dis-
tinctly banded. Splits parallel with the plane of the bands, but in other directions
has a conchoidal fracture. No individual constituents visible.
Microscopie Characters.—Generally similar to No. 1863, but not so dis-
tinctly foliated. It consists essentially of actinolite, quartz, and brownish mica, but
contains less quartz than the rock just described. The lepidoblastic ground fabric
consists almost entirely of actinolite prisms with a little interstitial quartz.
There are a few small porphyroblasts of a colourless prismatic mineral with its
long axes lying across the schistosity. This may be cyanite; it gives extinction
angles up to about 30° from its length, and in optical character, optical sign, optic
axial angle, and double refraction, answers to that mineral. The refractive index appears
to be somewhat low.
1855. ACTINOLITE SCHIST
Macroscopic Characters.—An extremely fine-grained black rock, finely
banded, some of the bands being strongly pyritic.
Microscopie Characters.The rock is distinctly banded, the alterations
in colour being due to differences in the character of the actinolite in the different
bands. The fabric is distinctly lepidoblastic on the whole, the essential constituents
being actinolite and colourless base with minor amounts of magnetite, calcite, and
greenish mica. In the dark bands the actinolite is very abundant, quite dark green
and strongly pleochroic :
a colourless ; ) and ¢ dark green.
COLLECTED AT CAPE ROYDS 185
In the lighter bands the actinolite appears at first sight to be granular, but between
crossed nicols it is shown to be optically continuous over areas of several square milli-
metres, so that the structure is poikiloblastic, approaching diablastic.
The colourless interstitial material is certainly complex; the greater part appears
to be quartz, but quite a considerable amount of it has a refractive index decidedly
greater than that of quartz and is probably untwinned basic felspar.
There are occasional flakes of colourless material answering to brucite.
265. Fine TREMOLITE-SCHIST
Microscopic Characters.—A very fine-grained and distinctly banded
lepidoblastic rock.
It consists essentially of quartz, scaly muscovite, and prismatic tremolite, with
slightly larger flakes of greenish clinochlor. Some of the bands are nematoblastic on
account of the aggregation of the tremolite prisms.
There are also present minute ovoid grains of a mineral, greenish to colourless with
a very high refractive index and strong double refraction, which, however, does not
seem to be epidote.
P. 239. Sporrep ScHIst
Microscopie Characters.—tIn section the spots are quite distinct: they
appear to contain the same colourless constituents as the remainder of the rock with-
out any of the biotite which occurs in the granulitic ground fabric.
The grainsize of the rock is very fine, which makes it very difficult to distinguish
the constituents.
The colourless mineral appears to be almost all quartz. The spotted appearance
is strikingly suggestive of development of incipient andalusite crystals, but no distinct
evidence of this mineral could be observed. There is a little magnetite present mostly
in the ground fabric, but occasionally in the spots as well.
602. PHYLLITE
Macroscopic Characters.—Chocolate-coloured rock, with well-developed
slaty cleavage. On the cleavage surfaces the lustre is satiny.
Microscopic Characters—tThe rock consists of angular quartz fragments,
many of them showing strain effects, cemented by a fine sericitic mortar, which is stained
with limonite.
464 (P. 89). Quartz ScHIST
Macroscopic Characters—A cherty-looking rock, of light yellowish-grey
colour and very close texture. The lustre is sub-resinous and fracture sub-conchoidal.
The rock is distinctly banded and its general appearance is extremely suggestive of a
limestone metasomatically replaced by silica.
Microscopic Characters—tThe rock is lepidoblastic, with a fine-grained
sround fabric (average grainsize about 0°1 mm.) containing “ auge” of quartz up to
2 mm. by 1 mm. The ground fabric consists of finely granular quartz and flaky
sericite with a very little epidote. The constituents show a slight tendency to segregate
into folia. There is a very peculiar arrangement of the ground fabric with two axes
of schistosity, making an angle of 40° with one another, so that, between crossed nicols,
when both sets of mica plates are illuminated, there is a decided meshwork. Here
and there the sericite is segregated into moderately large patches.
II 2c
186 PETROLOGICAL NOTES ON SOME ERRATICS
There are sporadic areas where epidote is fairly abundant im minute crystals with
rather dark colour.
The “auge” consist mostly of quartz without strain structure and probably
recrystallised. The long axes of these “auge” lie parallel to one of the axes of
schistosity above mentioned.
Amongst the quartz there occur large grains and crystals of pyrites in lamellar
intergrowth with magnetite. Also large flakes of phlogopite generally associated with
these composite grains.
There are a few rather conspicuous aggregates of secondary sphene and some larger
flakes of calcite.
450. Micackous SANDSTONE
Microscopical Characters.—Consists of angular and subangular grains and
flakes of quartz, and also of cherty material with a micaceous cement. There is a
well-marked stratification of the constituents. In addition to its presence as a fine-
textured scaly cement there are large flakes of mica, both muscovite and biotite. A
little ilmenite occurs also. Some of the quartz grains show signs of strain.
PLATES
EXPLANATION OF THE PLATES
PLATE I
Figure 1.—Microphotograph of rock 438 x 11 diameters (about).
Figure 2.—Microphotograph of rock E. 36 x 19 diameters. The colourless holo-
crystalline base consists of acid felspar intergrown with sodalite. The small, sharply
defined, dark prisms are wohlerite, bright orange in colour.
Figure 3.—The same x 55 diameters. Owing to the non-actinic colour of the larger
wohlerite crystals they have photographed black. The difference in refractive
index between the felspar and sodalite is indicated by the “ Becke’s effect.”
Figure 4.—Microphotograph of rock 443 x 11 diameters. The photograph contains
more than the normal proportion of biotite.
Figure 5.—Microphotograph of rock 372 x 18 diameters. The dark prisms are horn-
blende.
Figure 6.—Microphotograph of rock 7 x 55 diameters, showing the fine-grained
panidiomorphic mixture of hornblende, biotite, and felspar.
PLATE II
Figure 1.—Microphotograph of rock E. 11 x 19 diameters, showing the general aspect
of the rock with strongly corroded hornblende and corundum grains.
Ficure 2.—The same x 55 diameters, showing sharply idiomorphic phenocrysts of
anorthoclase.
Figure 3.—Microphotograph of rock 452 x 11 diameters.
Ficure 4.—The same x 62 diameters, showing the character of the composite horn-
blende crystals.
Figure 5.—Microphotograph of rock 440 x 31 diameters, showing well-defined tremolite.
Figure 6.—Microphotograph of rock 1278 x 55 diameters.
188
PLATE
Fic. 3 Hie. A
[To face p. 188
PLATE II
PART XII
REPORT ON THE PETROLOGY OF SOME
LIMESTONES FROM THE ANTARCTIC
(With Two Plates)
BY
ERNEST W. SKEATS, D.Sc., A.R.C.S., F.G.S.
Professor of Geology in the University of Melbourne
INTRODUCTION
Asout forty sections and eight hand-specimens of limestones were submitted to me
for examination by Mr. R. E. Priestley and Professor David. They represent
marine shallow-water limestones, some, possibly all, of Cambrian age, and contain
Archeocyathine, sponge spicules of colloid silica, etc. Many of the limestones have
been subjected to earth movements and veined with calcite and they present interesting
examples of metasomatic change, showing all stages of dolomitisation and silicification.
Staining with Lemberg’s solution and the attack with hydrofluoric acid were found
useful in investigating these two changes respectively.
Examples of regional dolomitisation were noticed, indicating/a shallow-water
origin for the limestone. This was confirmed by the presence of detrital fragments
of quartz, olivine, etc., in some of the rocks, and by the fact that some of the limestones
were oolitic. The oolitic grains show good concentric structures, possibly due to organic
tubules; many are dolomitised and silicified, and these show radial structures in
addition to the concentric. Some of these superficially resemble radiolaria but are
believed to be of inorganic origin. A comparison with dolomitised oolites from the
Transvaal has been made. Two limestones, in stu, from Farthest South were examined.
They contain Archewocyathine, and one of them a greenish material. A chemical
analysis of this rock has been made, and an estimate of the composition of the green
material, which may be a submarine tuff of an intermediate alkali rock, or may be,
since it contains a colourless micaceous mineral, detrital material.
DETAILED DESCRIPTIONS OF THE LIMESTONES
No. 8. Limestone Breccia. Cloudmaker, October 12, 1908. (P. 79.) (Erratic)
The rock is a limestone breccia. Large fragments of a fairly dense limestone,
containing no dolomite and traversed in places by secondary calcite veins, form the
bulk of the rock. The rest consists of an iron-stained brecciated area, in which
angular pieces of quartz and elongated fragments of muscovite are set in a ground-
mass of calcite. In some fragments micro-crystalline chalcedonic silica partly”
replaces calcite. Some calcite veins appear to fill cracks opened since the breccia
was formed, since they pass through not only the matrix of the rock but also across
the angular quartz fragments.
II 189 2D
190 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
No. 12. Dolomitic Limestone. Cloudmaker. (Erratic)
Two sections of this rock have been stained with Lemberg’s solution. The rock
is fine-grained, with minute fragments of limestone in a calcareous matrix. Scattered
through the rock are unstained areas of dolomite, mostly irregularly distributed, but
in places following lines of fracture. A few calcite veins also traverse the rock. The
rock therefore is a minutely fragmental dolomitic limestone.
No. 3. Limestone Breccia. Lower Glacier Depot, Beardmore Glacier,
October 12, 1908. (Erratic)
About twenty rock sections have been examined, mostly slices from one specimen.
The general characters are seen in the figure (Plate I, Fig. 1). The rock is strictly
a dolomitic breccia, and is interesting from its fossil content, structure, metasomatic
change, and origin.
Structure.—The rock is mainly composed of angular to rounded fragments of a
limestone which was completely dolomitised before being broken up. In some
sections, however, pieces of a calcareous and micaceous sandstone are seen (206, 207,
212), detrital fragments of chert (206, 207), dark cherty shale (212), or silicified oolite
limestone (209). Angular fragments of quartz resembling vein quartz are sometimes
abundant in the breccia: while sometimes elastic fragments of dolomite contain
water-worn fragments of quartz (212), or even other calcareous fragments (206).
Cracks in the original dolomitised and silicified limestone have been filled with calcite
before the rock was broken up and water-worn. Subsequently the fragments have
been cemented with calcite, the cemented breccia again cracked, and the cracks once
again filled with calcite.
Fossil content.—Several of the sections show traces of organisms. Archwocyathine
have been recognised, I believe, in some; but those which I have examined have been
so metasomatised that only the dark rims or “ ghosts” of the organisms now persist.
Metasomatism.—The water-worn pebbles of limestone in the breccia show that
their earlier history includes two types of metasomatic change involving the formation
of dolomite and of a silicified rock.
Dolomatisation.—Several of the rock sections have been stained with Lemberg’s
solution so that the dolomite and calcite could be precisely determined. The staining
has shown that the matrix of the breccia and the vein fillings, both those formed
before the pebbles and those of subsequent date, consist entirely of calcite. The
calcareous pebbles, with one doubtful exception, consist entirely of dolomite. The
dolomite is frequently cloudy, with central dark areas, and consists of interlocking
allotriomorphic crystals. Lining what were cavities in the rock are well-shaped
rhombohedra, some of which are zoned with altered chalybite, and occasionally with
calcite (3). From the fact that all the calcareous pebbles consist entirely of dolomite,
one may draw the conclusion that they have been derived from a limestone which
had not been merely locally dolomitised along cracks by later infiltrations of magnesian
waters, but had suffered complete regional submarine dolomitisation during the
formation of the limestone.
This observation is of special interest, as it indicates that the limestone was formed
in shallow water, a conclusion we are entitled to draw owing to the evidence of the
mode of occurrence of dolomite among ancient and modern coral limestones, as
recorded by Dr. Cullis and by the author, among others.* The shallow-water origin
* Cullis, Funafuti Report, 1904. Skeats, Bull. Mus. Comp. Zool. Harvard, vol. xiii, 1903,
p. 125. Q.J.G.S., vol. 1xi, 1905, pp. 133-187.
PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC 191
of the rock is also confirmed by the presence of detrital quartz fragments in some of
the dolomite pebbles (212), and by the fact that some of the pebbles show well-defined
oolitic structure (209), which, whether of organic or inorganic origin, is confined to
limestones of shallow-water origin.
Silicification.—Some of the dolomite pebbles and fragments have also been
silicified. The introduction of silica followed and did not precede dolomitisation.
This is clear from a study of the mode of occurrence of the silicified areas. These are
frequently irregular patches, appearing sometimes to fill up cavities in the rock which
had been lined by perfectly shaped rhombs of dolomite. In one section of the dolomite
breccia a fragment of a silicified and dolomitised oolitic limestone (209) occurs.
Replacement of the dolomitised oolitic grains and of the matrix by chalcedonic silica
is almost complete. A few rhombs of dolomite remain; the outlines of the oolitic
grains are ill defined, and later cracks through the pebble, formed since it reached
its present position, have been filled with calcite.
History.—A study of this dolomite breccia and its components suggests the
existence in the area whence the fragments were derived of a pre-Cambrian series of
igneous rocks, acid, and probably also basic and also of micaceous and calcareous sand-
stones. The Cambrian sea received fragments of these rocks along the shore-line
while the shallow-water Archwocyathine limestones were being laid down. Dolomitisa-
tion and silicification of the lmestones occurred, and at a later stage they were
elevated, disintegrated, seamed with veins of calcite and subsequently denuded. They
then provided the materials for a dolomitic breccia which, after consolidation by a
calcite matrix, was traversed by differential movements, forming cracks which were
again filled with calcite.
THE OOLITIC LIMESTONES
The presence of silicified oolite pebbles has already been noted in the description
of the dolomite breccia. Further evidence is obtained from erratics at two localities
at Cloudmaker. on the Beardmore Glacier, and also from among the erratics of Cape
Royds.
No. 20. Oolitic Limestone. Cloudmaker, Beardmore Glacier. (Hrratic)
Three sections of this rock were examined, of which two were stained with
Lemberg’s solution. Its appearance is shown in Plate I, Fig. 2, The rock shows
the very well-preserved oolitic or pisolitic structure, the grains being of large size,
ranging up to 4 mm., or about {th inch in diameter. The majority of them are
spherical in shape, but some are elongated, and others have been fractured. One or
two examples of double oolitic grains were seen. The central part of the grain appears
usually to have been recrystallised, and consists now of large interlocking crystals,
mostly of calcite. No radial structure is noticeable, but the concentric layers are
well preserved. The layers appear to consist of minute tubes, which are occasionally
not arranged concentrically, and this would appear to support the view that these
large oolitic or pisolitic grains are of organic origin. The matrix of the rock, like the
centre of the grains, has been recrystallised to a calcite mosaic. The rock also shows
partial dolomitisation. Much of the dolomite appears to be sporadic in occurrence,
but some crystals are definitely placed along cracks in the rock.
Except along cracks, the general matrix of the rock has not been dolomitised.
The oolitic grains, particularly their central parts, are noticeably dolomitised, the
salient angles of the rhombs in places advancing into the marginal part, which shows
the concentric structure. All stages in the replacement of the oolitic grains can be
192 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
seen. In a few cases the whole of the grain, periphery as well as nucleus, has been
completely converted into dolomite.
These areas show up well by their freedom from stain after treatment of the rock
with Lemberg’s solution. In places, however, these large crystals of dolomite include
minute areas of unaltered calcite, as is shown by the slight difference in refractive
index and by the staining of such areas.
Silicified Oolitic Limestone. Cape Royds. (Erratic)
Nine sections labelled as above have been examined; seven of these have been
sliced from the same specimen, and two, numbered P. 86, have different characters.
P. 86.—The two sections examined consist entirely of chalcedonic silica and
dolomite rhombs. The dolomite rhombs are arranged as minute irregular rings, the
long ones ranging from about ;!; to } mm. The central parts of the rings and the
matrix between them consist of chalcedonic silica, There can be no doubt that the
rock was originally calcareous, and afterwards at any rate partially dolomitised.
Possibly parts which remained as calcite were then dissolved away, and secondary
chalcedonic silica filled the spaces so left. A few calcareous centres to the rings of
dolomite are to be seen, but the remainder of the ring-centres in ordinary light show
a colourless and structureless infilling of silica. The origin of these ring-shaped areas
is doubtful. They may represent remains of oolite grains distorted in shape after
the removal by solution of the central areas, but they are of much smaller dimensions
than the undoubted oolites, and no positive opinion can be expressed.
The remaining seven sections (Nos. 222, 233, 240, 244, 245, and two un-
numbered ones) all show fairly uniform characters, which are seen in Plate I, Figs. 3
and 4.
General characters.—They are all dolomitised and silicified oolitic limestones. The
average diameter of the grains is about } mm., while that of the grains from Cloud-
maker is, as previously noted, about 4 mm.
A few irregular, structureless pellets occur, some of which consist of dolomite,
others are partially or wholly silicified. A few composite oolitic grains occur, but
the large majority are simple, and nearly spherical in shape. In these silicified rocks
a few of the oolite grains show the concentric structure only, the great majority
having a central nucleus, an outer margin showing concentric structure, and a middle
layer with a well-pronounced radial structure.
Comparison with radiolaria.—So closely do these latter oolitic grains resemble
radiolaria on first inspection that I have paid particular attention to them and
instituted careful comparisons with recent and fossil radiolaria. I have been led to
abandon the idea that they might be radiolaria for the following reasons :
(1) Size.—The average diameter is about 5 mm., while the diameters of most of
the recent and fossil radiolaria I have measured ranged between ‘08 and ‘3 mm.
(2) Structure.—(a) There is no trace of the reticulated or mesh structure as seen
in the skeletons of radiolaria.
(b) Instead of a uniform series of concentric layers at fairly wide intervals, as is
usual in many radiolaria, these grains show commonly several closely adherent layers
round the outer margin of the grains—a feature characterising undoubted oolitic
grains.
(c) The radial appearance seen is probably due to crystallisation and not to organic
structure, for in the case of the composite grains not only is it seen in the individual
grains but it occurs also in the outer part of the composite grain.
(3) Composition.—There can be little doubt that the original composition of the
PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC 193
rock, both matrix and grains, was calcareous, and that subsequently dolomitisation
and afterwards silicification occurred. In accordance with this, it is found that in
places the matrix remains as dolomite, some of the indifferentiated pellets persist as
dolomite, some of the oolitic grains are also entirely preserved in dolomite, and where
the grains have been silicified the concentric and radial structures are usually defined
by minute rhombohedra of dolomite. On the view that the radial structures were
the skeletons of radiolaria, one would have to assume that the siliceous network was
first replaced by dolomite, and that later extensive silicification of the rock replaced
most of the matrix and filled the spaces between the radial and concentric structures.
There is no warrant for this view, and all the evidence points to the original composition
being calcareous.
Staining and acid attack.—Two of the sections were stained with Lemberg’s
solution with negative results, demonstrating that the minute rhombohedra are
dolomite and not calcite. In the case of one section, where the rock had been silicified
to a varying extent in different parts, it was found that the structure of the oolitic
grains was only faintly visible in some cases, as all the dolomite rhombs had been
replaced by chalcedonic cryptocrystalline silica. One half of this section was then
attacked by hydrofluoric acid, with the result that the radial and concentric structures
of the silicified grains were rendered more clearly visible owing to a differential attack
of the acid. The chalcedonic silica of the matrix was also unequally attacked,
bringing out a banded agate structure, which was previously not noticed (see Plate I,
Fig. 1). Possibly the calcareous matrix surrounding the grains had been dissolved
out, and later the silica was deposited in concentric layers round the grains.
Structure and metasomatism in the oolitic grains—From the above it will be
clear that in the oolitic rocks which have remained calcareous only the concentric
structure was seen, while both concentric and radial structures occur in each section
of the silicified rocks. The following statement defines the types of structure
and the probable order of metasomatic change in the oolitic limestones. The types
are separated for clearness of statement, but many of them occur together in the
same section, showing that in the same rock metasomatic changes affected separate
grains in different degree.
PureLy CaLcargEous TyYPEs
(1) Oolitic limestones composed entirely of calcite, the oolitic grains showing
concentric structure only. The matrix consists of coarse interlocking crystals of
calcite. Example: Cloudmaker, Beardmore Glacier, No. 20.
(2) Dolomatised oolite.
(a) Partially dolomitised. Generally the nucleus is alone dolomitised. Con-
centric structure shown. (No. 20.)
(b) Completely dolomitised. All structure destroyed. (No. 20.)
SILICIFIED TYPES
In these rocks both matrix and grains have been silicified in varying degree.
The matriz.—The matrix occasionally retains some dolomite, but for the most
part it is siliceous, and ranges from ecryptocrystalline chalcedonic silica to a definite
quartz mosaic. Attack with hydrofluoric acid, as noted above, develops a banded
agate structure in the matrix. It is noted that when both matrix and oolitic grains
are silicified the silica of the grains is usually cryptocrystalline and finer in texture
than that of the surrounding matrix.
194 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
(3) The oolitic grains.
Completely dolomitised oolite, but showing both radial and concentric structures.
(4) Dolomitised and silicified oolitie grains.
(a) With both concentric and radial structures.
(6) With only concentric structure.
(c) With central structureless silicified part and outer ring of dolomite.
(5) Silicified oolitic grains in which all dolomite has been replaced by silica.
(a) With concentric and radial structure.
(b) With concentric structure alone.
(c) Spherical in shape, but structureless.
A rather interesting resemblance is noticeable between these silicified oolitic
limestones and certain siliceous and dolomitic oolites occurring among the probably
pre-Cambrian dolomites of the Transvaal. Two sections from Krugersdorp, in my
possession, show oolitic grains with concentric and radial structures preserved in
dolomite more or less completely replaced by chalcedonic silica. The matrix of the
rocks is also partly siliceous, partly calcareous.
P. 282. Stranded Moraine, Kast Fork, Ferrar Glacier. (Erratic)
A very fine-grained dense limestone, whether dolomite or calcite cannot be
determined, as opportunity for staining was wanting. The interest of this rock
depends upon the presence of volcanic fragments and minerals and of fossils (Plate IT,
Fig. 2). The volcanic material consists of angular, brown, iron-stained fragments
and of crystals of biotite. A little quartz is also present as minute fragments. This
material may be of detrital origin, but it is suggestive of the intermixture of particles
of a submarine tuff in a marine limestone. The fossils noticed are several broken
pieces of sponge-spicules. The fragments are each in length about two or three times
the diameter of the spicule. In each case the central canal is clearly preserved, and
the silica remains in its original colloidal form. A comparison with some sponge-
spicules of Tertiary age shows a similar freshness, comparable dimensions, and in
each case a refractive index lower than that of Canada balsam. These fragments do
not present characters definite enough for identification, and so yield no direct
information as to the age of the limestone. As remains of Archaocyathine are believed
to occur in some of the Antarctic limestones, the question arises whether these spicules
may be of Cambrian age. In general form, dimensions, and the relation of diameter
of the canal to that of the whole spicule they are similar to some sponge-spicules I
found in cherty rocks of the Heathcotian series in Victoria (L. Ordovician or U.
Cambrian ?). Dr. Hinde kindly examined these for me and confirmed their identifica-
tion as sponge-spicules, but could not name them. These Heathcotian spicules are
recrystallised to chalcedonic silica. While, then, the preservation of the colloidal
character of the spicules in the Antarctic rock suggests that the rock has no great
geological antiquity, there is nothing in their form and structure to negative the idea
of a Cambrian age for the rock if that is indicated by other evidence.
No. 15. Cloudmaker, Beardmore Glacier, December 10, 1908. (Hvratic)
A limestone which has been extensively shattered and recrystallised. In con-
sequence the rock now consists mainly of large interlocking, frequently twinned, and
cloudy crystals of calcite. Staining with Lemberg’s solution shows that along the
structural cracks in the rock magnesian solutions have entered, with the production
PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC 195
of crystals of dolomite more or less confined to the fractured areas. Still later cracks
have been healed by the deposition of clear twinned crystals of calcite.
P. 301. Marble. Stranded Moraine. (Erratic)
The rock is a recrystallised limestone. It consists now mainly of large, inter-
locking, twinned crystals of calcite, one or two pieces of quartz, some opaque
fragments of graphite and of pyrite altering to limonite, and a number of small
colourless crystals of tale. The tale is recognised by having a fairly low refractive
index, high polarisation colours in prismatic sections, by giving a pseudo-uniaxial
and negative interference figure, and by its micaceous habit. The tale may have
been developed in the rock during recrystallisation, and may be the product of
dedolomitisation of a sliyhtly siliceous and magnesian limestone. The quartz and
opaque material, however, appear to be detrital, and the tale may have a similar
mode of origin.
P. 305. Dry Valley, Antarctic. (Hrratic)
A carbonate forms the bulk of this rock. The section was mounted unstained, so
it remains uncertain whether the mineral is calcite or dolomite; probably it is the
former. Several detrital grains of olivine, more or less altered to serpentine, are
scattered through the rock. Minute crystals of pyrite are also present. Reddish-
yellow ferric hydroxide occurs in irregular areas or surrounding opaque masses of some
iron mineral. Irregular patches of graphite are noticeable in places. In addition
there are scattered through the rock a number of irregular-shaped sections of a
colourless mineral with a refractive index a little higher than that of Canada balsam.
The majority of the sections show no cleavage and low polarisation colours; while
the sections showing cleavage exhibit bright colours. In convergent light pseudo-
uniaxial or slightly biaxial figures are seen. The sign is negative. The mineral is
therefore almost certainly tale. The olivine in the rock is certainly of detrital origin,
and its presence indicates that the limestone formed near a shore-line consisting in
part of basic igneous rocks. The tale may be detrital, but from its irregular
boundaries with the limestone may have developed in the rock by the alteration of
a magnesian mineral. The rock is a limestone of shallow-water origin.
K1. Dunlop Island ; between Cape Bernacchi and
Granite Harbour. (Erratic)
This is a very fine-grained rock, consisting of minute allotriomorphic granules of
a single material, which is probably dolomite.
P. 268. Dunlop Island. (Hrratic)
This section is exactly similar to K1 described above.
No. 4. Detrital Rock. Cloudmaker, December 10, 1908. (Hrratzc)
This rock is not a limestone, but an altered detrital rock. The hand-specimen
is very hard and compact. Under the microscope irregular minute yellow-brown
specks of hydrated oxide of iron are distributed through the rock, and a few irregular
grains with fairly high refractive index and bright polarisation colours consist probably
of a pyroxene.
196 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
The bulk of the rock is a colourless groundmass which in polarised light consists
of a cryptocrystalline to microcrystalline arrangement of crystals polarising in neutral
tints. Some are rectangular in outline, and may be felspar; the majority are irregular
in shape, and consist probably of chalcedonic silica. The rock presents considerable
resemblance to a fine-grained spilosite, but may be a dense ferruginous chert.
LIMESTONES IN SITU FROM FARTHEST SouTH
Two specimens brought back from Farthest South owe their importance to their
geographical position, to the fact that they were taken from rocks in situ, and to
the fact that the discovery in them of Archeocyathine fixes their age as Lower
Cambrian.
No. 106. Farthest South.* December 20, 1908. (In situ)
Six sections of this rock have been examined, five mounted in the ordinary way,
the sixth after staining with Lemberg’s solution. The hand-specimen is a grey,
dense limestone, with a few lighter calcite veins and specks of pyrite scattered
through it.
Under the microscope staining shows that the rock consists chiefly of calcite, with
a subordinate development of dolomite. For the most part the dolomite is developed
in sporadic crystals throughout the rock. In places, however, it occurs along cracks,
and at one point a large number of well-developed rhombohedra are grouped
together with a calcite background. The rhombohedra of dolomite have cloudy
centres and clear margins. This cloudy material is for the most part dolomite, since
it is unstained; but in two cases the kernel of the crystal consists of calcite and the
margin of clear dolomite in optical continuity with the calcite. The rock is slightly
mineralised, as cubes of pyrite are sparsely scattered through it. There are faint
indications of the former presence of organisms, and structurally the rock has been
subjected to considerable earth movements. Some of the cracks lined with dark
material or with dolomite crystals show a very tortuous passage through the rock,
indicating later squeezing. The latest movements induced straighter cracks, now
filled with clearer, larger crystals of calcite than in the matrix, which consists of
somewhat cloudy allotriomorphic calcite crystals.
No. 107. Farthest South, December 20, 1908. (In sitw)
The hand-specimen is a dense, fine-grained rock with irregular streaks of a green
material distributed through it.
Two sections have been examined, of which one was stained with Lemberg’s
solution (Plate I, Figs. 3and 4). No dolomite can be recognised, the whole of the back-
ground of the rock consisting of minute greyish granules of calcite, except for a few
micaceous particles. Obscure traces of fossils, including Archwocyathine, can be
seen. A point of considerable interest is the nature and origin of the material, which
has a greenish appearance in the hand-specimen. Under the microscope it is very
fine-grained, and is barely resolved under a }-inch objective.
Chemical composition.—With the idea that a chemical analysis would help in the
elucidation of this question, I asked Mr. F. L. Stillwell, B.Sc., Kernot Research
Scholar in Geology in the University of Melbourne, to undertake this for me. I am
much indebted to Mr. Stillwell for the care and time he has given to this work. He
* This refers to the ‘farthest south” outerop of rock in this vicinity; not the farthest south
point reached by the party.
PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC 197
took several grammes of the rock, ground it very fine, and took one gramme from this
powder for a bulk analysis. The result is as follows:
S10, = 22:19
Al,O3 = 6:05
Fe,0, = 1:30
FeO = 1°55
110), = 0°55
CaO = 34°44
MgO = 1:98
K,0 = 251
Na,O = 1:96
CO, = 26°55
H,O — (below 110 °) = up
H,O +. ; = 92
100°46
An attempt was made to determine the composition of the green material by
dissolving the carbonates in dilute hydrochloric acid (1 in 6) and analysing the
insoluble residue. It was found, however, that the acid had attacked a part of the
green material, since 2 per cent. of S10, and 3 per cent. of Al,O, occurred in the
soluble portion, and this attempt was abandoned. The composition of the green
material was eventually arrived at by alloting all the CO, to the lime and magnesia
in the analysis and expressing the result as carbonates of lime and magnesia. For
this purpose the assumption was made that the carbonates are present in the rock in
the same proportions as the oxides in the analysis. In this way the carbonates were
determined as follows:
CaCO, . 3 ; 56°82
MgCO, . : : : 5 ; 2:98
59°80
After satisfying the carbon dioxide with lime and magnesia an excess of 2°62 per
cent. of the former and ‘56 of the latter remained, which was allotted to the remainder
of the rock. This has the composition shown in Column I. Calculated to 100 per cent.
it is shown in Column II.
D II
S1Oo. : : 9 3 0 22°19 3 4 54°55
Al, O, : ; ‘ é 5 : 6°05 : : 14°85
Fe, 0, : : : : : : 1°30 : ¢ 3°20
FeO ; : : : : . 1°55 : : 3°81
On = : ; ; : : "55 , 1°35
CaOay o: ; ; : : : 2°62 : : 6°44
MgO. : ; : 4 : 56 : ; 1°38
Oo OMe MS Mus etre scl Vd y Oc 617
iE Dy re eee Pea 1,96y. G04 |/<. 4-82
EO bSrsert Lee Vil Gat, Tey aa AG Ob a 113
POPE Pet Beat aL A we. GOte egos Ald: 2-26
40°67 : : 99°96
II
198 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
Microscopic characters of the green material—Examination under a one-inch
objective showed the green material to be composite in character, and to be distributed.
in streaks which passed through the rock in an irregular way. A thick band tails
out in a short distance to a thin filament or branches into a number of threads
traversing the limestone. It is difficult to decide whether this is an original arrange-
ment due to irregularity in deposition or whether the irregularity has been sub-
sequently induced by pressure. Under a }-inch objective the most prominent mineral
is a colourless to pale greenish micaceous mineral, showing sometimes fairly bright
polarisation colours. A good deal of the greenish area, however, shows low polarisation
colours in the first order, and in places minute felspar crystals appear to be present.
In addition minute brownish specks represent oxide of iron, possibly an alteration
product of a ferro-magnesian mineral, and some rather highly refracting fragments
appear to be isotropic.
Nature and origin of the green material.—Two alternatives present themselves as to
the nature of this material: It may be very fine-grained detrital material washed out
from a shore-line and deposited with mica among the calcareous matter of the
limestone. On this view its irregular distribution through the rock would be accounted
for by the subsequent irregular squeezing of the limestone during earth movements.
On the other hand, it may be a submarine tuff. On this view its peculiarities of
distribution might be to some extent original and connected with explosive discharge
and irregular settling from a neighbouring vent.
If the material consists of tuff fragments its chemical composition should help to
place it.
In the American classification the norm calculated from its chemical composition
is as follows:
Orthoclase . ; 5 ; : : 36°70
Albite ; : ; ; : : 24°63
Anorthite . ; ; ; : ‘ 83
Nephelite . ; : : : : 8:80
Diopside . ; ! ; ; ; 11°53
Wollastonite : ; 5 A ; 7:08
Magnetite . ‘ : , : F 4°64
Ilmenite . : 5 : : : 2°58
Its position in the classification is :
Class IT., Dosalane.
Order V., Germanare.
Rang I., Peralkalic-Umptekase.
Subrang III., Sodi-potassic IImenose.
This is a subrang including a few rocks such as representatives of the porphyrites,
kersantites, and rather basic alkali trachytes. The analysis of a porphyrite from
Thuringia comes closest to it.
In determining the probable nature of the green material we have, then, the choice
between a tuff from a rather alkali intermediate rock such as a porphyrite or somewhat
basic trachyte on the one hand and fine-grained micaceous detrital material on the
other. The available evidence is not sufficient to enable a positive choice to be made,
but the presence of a considerable amount of the colourless micaceous mineral
suggests that the detrital view of its origin may be the correct one.
EXPLANATION OF THE PLATES
PLATE I
Figure 1.—No. 3. x 5. Dolomitic breccia with Archeocyathine, Beardmore Glacier.
Rounded and angular fragments of dolomitised limestone with angular and
crushed quartz fragments are set in a matrix of calcite. Later veins of calcite
traverse the larger fragments and the matrix.
Ficure 2.—No. 20. x 12. Dolomitic oolrtic limestone.
Several grains show good concentric structure, one grain in the centre of the field
is largely replaced by dolomite and three defined rhombohedra of dolomite have
invaded the concentric layers of a grain near the upper part of the field. The
matrix is chiefly clear calcite.
Figure 3.—No. 245. x 12. Silicified oolite from erratic at Cape Royds.
The grains show both concentric and radial structures. One composite grain is
seen near the lower part of the field. The substance of the grains is chiefly dolo-
mite with partial replacement by metasomatic silica. The groundmass is partly
dolomite but sporadic clear areas of chalcedonic silica indicate partial metasomatic
replacement.
Figure 4.—No. 240. x 28. Silicified oolite from erratic at Cape Royds.
A good example of a dolomitised grain showing radial structure, another con-
centric and a third composite are seen. An irregular pellet, dolomitised and
silicified, has its boundary defined by a dark layer. The matrix is now mainly
chalcedonic silica.
PLATE II
Figure 1—No. X. x 28. Szlicified oolite from erratic at Cape Royds.
Several stages in the silicification of dolomitised oolitic grains are seen. The
original matrix has been mainly replaced by chalcedonic silica. Attack by hydro-
fluoric acid has affected the silica unequally and has developed an agate structure
between the individual grains.
goes 2.—P. 282. x 277. Limestone from Stranded Moraine, East Fork, Ferrar
tlacier.
_A fine-grained limestone with two or three fragments of sponge spicules. One
spicular fragment showing the central canal is seen above the centre of the field.
199
200 PETROLOGY OF SOME LIMESTONES FROM THE ANTARCTIC
Ficure 3.—No. 107. x 29. Limestone, Farthest South, December 20, 1908. (In situ.)
A non-dolomitised limestone with irregular bands of insoluble material in-
cluding a pale greenish micaceous mineral. These bands may be detrital in origin
or may be pyroclastic.
Ficure 4.—No. 107. x 83. Limestone, Farthest South, December 20, 1908. (In situ.)
The same as Figure 3, but more highly magnified and showing better the nature
and arrangement of the band of greenish insoluble material.
All the negatives were taken by Mr. H. J. Grayson, and in ordinary light.
PLATE
No. 3. x 5 diams. No. 20. < 12 diams.
Fic. 1 Fic. 2
Limestone breccia, Cloudmaker, with fragments Cloudmaker, Beardmore Glacier. Partially
of Arehzocyathine dolomitised limestone, dolomitised oolitic limestone.
quartz fragments and later calcite veins.
No. 245. < 12 diams. No. 240. < 28 diams
Fic. 3 Fic. 4
Erratic, Cape Royds. Dolomitised and partially Erratic, Cape Royds. Dolomitised and partially
silicified oolitic limestone. silicified oolitic limestone.
[To face p. 200
PLATE II
300 diams.
No. X. 28 diams No. P. 282.
Fic. 1 Fie. 2
Erratic, Cape Royds. Etched with Hydrofluoric Stranded Moraine, East Fork, Ferrar Glacier. Dense
acid. Dolomitised and silicified oolitic limestone limestone with voleanic fragments, quartz, and fresh
sponge spicule.
with banded agate structure in matrix.
x 90 diams.
No. 107
No. 107. 25 diams.
Fic. 4
Fic. 3
Farthest South, December 20,1908. Jn situ Farthest South, December 20,1908. In situ,
with Lemberg’s — solution Archiro- Stained with Lemberg’s solution. Archieo-
cyathinw limestone with greenish veins of
Stained
eyathine limestone with
detrital or tuffaceous material. detrital or tuffaceous material.
greenish veins of
PART XHUlI
PETROLOGY OF ROCK COLLECTIONS
FROM THE MAINLAND OF SOUTH VICTORIA LAND
BY
D. MAWSON, DSc,, B.E.
University of Adelaide
CONTENTS
THE SEDIMENTARY ROCKS
Tue PSEPHITES
THE PSAMMITES
THE PELITES
THE IGNEOUS ROCKS .
THE GRANITES AND AssociIATED Dyke Rocks
The Pink Granites
The Grey Granites
The Granite Porphyries
The Felspar and Quartz Porphyries
The Aplitic Granite Porphyries
The Aplites .
The Pegmatites
The Lamprophyres
The Basic Inclusions
Tue Diorires
THE GABBROS
THE RECENT VOLCANIC SERIES
THE METAMORPHIC ROCKS
METAMORPHISM OF THE GRANITES
METAMORPHISM OF THE Bastc IGNEous Rocks
METAMORPHOSED SEDIMENTS
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PETROLOGY OF ROCK COLLECTIONS
FROM THE MAINLAND OF SOUTH VICTORIA LAND
BY
D. MAWSON, D.Sc., B.E.
University of Adelaide
THE material described is included in three collections made respectively by the Southern
Party from the vicinity of the Beardmore Glacier 83° 50’ to 85° 10’ 8. lat. ; the Western
Party from the Ferrar Glacier region, 78° 8. lat., and the Magnetic Pole Party* from the
coast-line between 78° and 75° 8. lat. The geological conditions over this region appear
to be very similar. For this and other reasons it is found advisable to tabulate under
one scheme the specimens from all three sources. In most cases the specimens were
collected as erratics ; when otherwise the fact is expressly stated.
THE SEDIMENTARY ROCKS
Typical conglomerates, sandstones, slates, limestones, and even carbonaceous shales
and sandstones, as well as true coal, are exemplified. These argue water conditions
and a milder climate than now prevails in those latitudes. There are, nevertheless,
often present certain characters which indicate a severe and almost glacial climate.
The diagnosis of deposition under semi-glacial conditions lies in the intimate character
of the rocks as revealed by microscopic study and analysis. The thick arkose and
greywacke formations I regard as corresponding to such semi-glacial conditions. I
have arrived at this conclusion after a detailed study of the glacial and interglacial
sediments in Australia corresponding with the Cambrian and Permo-Carboniferous
ice ages. ‘Similar arkoses and greywackes, as well as unleached muddy silts, invariably
accompany these tillite horizons, often repeated many times in waning sequence above
and below the latter. This recurrence indicates the continuance of strophic periods.
Examples of true tillite are almost absent amongst the collection : these are limited
to several pieces of a recent character from the coastal moraines of McMurdo Sound,
and a scrap of an older-looking type from a moraine at sea-level near Mount Larsen.
In the valleys inundated with summer waters in the Ferrar Glacier region there
is evidence that deposition of travertine is now taking place. Travertine is found
coating the pebbles and even cementing gravel to form a hard rock.
The existing arid conditions, united with the fact that complete ablation of snow
and ice masses usually takes place before a melting temperature is reached, result in
the concentration of any contained dissolved salts. Thus residues of sodium, magnesium,
and lime sulphates and chlorides are of frequent occurrence.
* The MS. of this paper was received by the General Editor in September 1911. Subsequently
Sceott’s Northern Party, in 1912, recovered the collection of rocks cached and unretrieved by us at
Depot Island. In my absence in Antarctica the Depot Island collection has been described by
Mr. L. Cotton and forms a further section of this volume.—D. M., January 1916.
il 203 2G
204 PETROLOGY OF ROCK COLLECTIONS
PSEPHITES
The conglomerates are almost all referable to the Beacon Sandstone formation,
and usually represent pebbly bands interlaminated with the fine-grained sandstone.
It is safe to assume that the base of the series is a definite conglomerate horizon, as
coarse examples, likely to have come from such a situation, are met with in the recent
moraines. A specimen of such a conglomerate from the Knob Head Mountain Scree,*
west (Ferrar Glacier), is at hand. In it there isa general absence of anything but quartz,
of which the pebbles range up to 3 cm. in diameter, and are very firmly cemented
together.
A conglomerate of a much later age appears amongst the material from the Stranded
Moraines, McMurdo Sound, and from Dry Valley, New Harbour. It is suggestive of a
recent age, and, as it contains fragments of the mainland dolerite. it is almost certainly
Tertiary or Post-Tertiary. Its constituents have accumulated under water and the
pebbles are not obviously glaciated. The constituents comprise biotite, muscovite,
felspar, crystal quartz, jasper, chert, and composite rocks ; amongst the latter are dolerite
and a pre-existing grit consisting chiefly of white and crystal quartz. Cementing these
there is an abundance of a light yellow mud consisting mainly of carbonates of lime and
magnesia. This rock appears to tally with that mentioned by Dr. Prior } as occurring on
the western promontory of Black Island. Its characteristics suggest an aqueo-glacial
origin and its distribution infers deposition in recent times in connection with the
affluent streams and ponded waters at the termini of the large mainland glaciers.
PSAMMITES
These are chiefly sandstones and arkoses, which are represented in varying degree
of metamorphism. By a study of the moraine-derived specimens it is not possible
to say how far the quartzites represent the Beacon Sandstone, or to what extent they
proceed from older formations. Amongst the metamorphic rocks are sandstones and
ereywackes intruded by granite; this infers a certain antiquity for the intruded
sediments.
In the collection from the East Fork of the Ferrar Glacier is a very white fine-
grained quartzite ; between this quartzite and an almost pure marble, graduated steps
are represented by other specimens. These marbles are thought to be of Palzozoic
age, and the inference is that quartzites, also of this age, exist.
The facies of the Beacon Sandstone formation is so distinctive that one has no
hesitation in referring almost all the psammites to this formation. A collective des-
cription will be found most convenient.
THE BEACON SANDSTONE
A wide geographical range is indicated by its appearance in all the mainland col-
lections. Amongst the collection made by Priestley in the Ferrar Glacier region it is
most typical and abundant. The Southern Party met abundance of the more fel-
spathic varieties between 83° 50’ S. lat. and 85° 10’ S. lat. A few fragments only were
met with by the Magnetic Pole Party, though the topographical features of the coast
ranges in that direction infer its continuance northward on a grand scale.
The constitution of this rock varies through wide limits, from a nearly pure quartzose
* For maps refer to vol. i of these Reports.
+ British Museum Reports on National Antarctic Expedition, 1901-4, vol. 1, Geology, p. 139.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 205
sandstone to a highly felspathic arkose. The former is the typical Beacon Sandstone
described in Dr. Prior’s reports.* In point of general description nothing remains to
be recorded more than is therein detailed. Exceptional features are, however, abundant
and worth notice.
The usual characters are a medium-grained sandstone composed of angular or
somewhat rounded grains of quartz usually but loosely cemented together ; accessory
ingredients such as felspar, garnet, and rutile are quite common. The cementing
material, usually siliceous, is frequently calcareous. The typical sandstone passes over
on the one side to conglomerate or arkose and on the other to much fine-grained
saccharoidal varieties (Fig. 1, Plate I).
A sample of this latter variety, from Dry Valley, grades from a very white sac-
charoidal sandstone above into a band below, studded with partially abraded quartz
pebbles as muchas 18mm.long. The sand grains are sub-angular, frequently exhibiting
shining crystal faces, and are but loosely adhering. Quite fresh felspar grains are not
uncommon. The grain size averages 0-75 mm. A crystal of gypsum was noted
adhering to the wall of a cavity in this specimen.
In a specimen from the Lower Medial Moraine, Ferrar Glacier, fragments of grey-
blue shale appear. These exactly resemble similar inclusions in the psammites of the
older glacial horizons of Australia. Some specimens collected opposite the Cathedral
Rocks, Ferrar Glacier, are highly felspathic ; some are strongly and others loosely
cemented.
In some specimens the grains are much more rounded, as in the case of a very white
rock from Knob Head Mountain Scree, Ferrar Glacier, in which the quartz grains are
embedded in a kaolin base.
This latter type is usually closely associated with carbonaceous varieties. A
specimen of such a rock from the moraine below Cathedral Rocks contains quartz,
some felspar, and occasional faintly pink garnet in fairly well rounded grains. The
carbonaceous matter follows along certain planes of deposition associated with
accumulations of silt. Muscovite plates are conspicuous along these planes.
An exceptional tinted variety is one from the Medial Moraine, Ferrar Glacier,
where the interstices are filled with a chloritic substance contributing a greenish
colour.
Quartzites of essentially the same characters but almost flinty in fracture, met with
amongst the moraines of the Ferrar Glacier, are regarded as Beacon Sandstone meta-
morphosed, probably by local igneous action.
Ferrar and Prior + have referred to stalagmitic and marbled forms of the Beacon
Sandstone. This is due to unequal cementation in the sandy beds, perhaps resulting
from local infiltration of alkaline solutions. Weathering processes often result in
stalagmitic relief; at other times concretionary forms are developed. Numerous
examples of the latter occur in Priestley’s collections from the Knob Head Mountain
Scree, and from the Medial Moraine opposite Cathedral Rocks, Ferrar Glacier. These
concretionary nodules are spherical (Fig. 2, Plate 1) and saucer-shaped (Fig. 3, Plate I).
The former, though cemented firmly in the peripheral zone, often contain within much
calcareous and clayey matter. The central portions are thus but loosely cemented. When,
in nature, fracture of the hard shell takes place, due to accidental circumstances, the
softer central portions are quickly removed by wind erosion and the concretions are
hollowed out (Fig. 2, Plate I). Jn situ, these concretions appear either as spherical
balls in relief or, where hollowed out, as wells sunk in the weathered surface. On
slicing a completely spherical specimen 7 cm. diameter it was found to consist of an
* British Museum Reports on National Antarctic Expedition, 1901-4, vol. i, Geology.
+ Ibid., p. 139.
206 PETROLOGY OF ROCK COLLECTIONS
outer shell 1-2 cm. diameter in which the quartz particles are cemented by growth-
enlargment of the grains themselves, and of an interior filling 4-6 cm. diameter of
quartz grains cemented by calcite in optical continuity. Obviously the localisation
of alkaline substances or calcite has determined the formation of these concretions.
One fragment of the Beacon Sandstone formation from the Moraine, Hast Fork of
the Ferrar Glacier, is loaded with calcite in optical continuity. A similar Fontainbleau
Sandstone occurs directly above the Permo-Carboniferous tillite at Hallett’s Cove, South
Australia.* It appears to be commonly the case that mechanical sediments of glacial
periods become loaded with calcite or other chemical precipitate.
Certain specimens from the East Fork of the Ferrar Glacier, obviously belonging
to the Beacon Sandstone horizon, are highly felspathic. They contain quartz, ortho-
clase, acid plagioclase, muscovite, biotite, pink garnet, rutile, and iron ores. ‘This is
a transition towards the typical psammite of the Beardmore Glacier area, whichis an
arkose quite remarkable in character and deserving a special description. There seems
to be no reason to doubt its identity as an example of the Beacon Sandstone formation.
Its peculiar characters are just such as would be expected from rapid disintegration
under semi-glacial conditions. Carbonaceous material appears along the bedding
planes of some of the specimens, just as is the case in the specimens from the Ferrar
Glacier.
The following description refers to the more massive varieties free from organic
matter.
ARKOSE FROM THE Upper GLACIER Depot, BEARDMORE GLACIER
The hand-specimen is an even-grained sand-rock of an ash-grey colour. A large
proportion of felspathic material, partly kaolinised, is present. Particles of mica are
not infrequent, most abundantly distributed along the bedding planes ; this endows
the rock with a ready fissility. With the aid of a pocket-lens particles of pink garnet
are rendered obvious.
A microscopic examination showed it to be composed of particles averaging in the
prepared slide 0-12 mm. diameter.f (Figs. 1 and 2, Plate III). The grains have
angular and sub-angular boundaries with splintered edges.
Quartz is the chief constituent. Under crossed nicols most of the particles exhibit
strain shadows or are seen to have suffered crushing by granulation. Frequently a
rejuvenation is evidenced by clearer border zones. Abundant inclusions, chiefly
rutile needles, are present. The felspars are predominantly orthoclase, microcline, and
anorthoclase, though a minor proportion show albite lamelle and agree in optical
properties with albite and oligoclase. They have a dusty appearance in transmitted
light due to partial kaolinisation, and certain grains show chloritic changes. Under
crossed nicols the effects of strain are again noted. Mica, both muscovite and biotite,
is present sparingly, in small particles, usually partly converted to chlorite and often
much bent. Apatite in occasional inconspicuous grains. Particles, originally amenite,
now altered to leucovene, are frequent. Pink garnet in small quantity, often embedded
in the felspar individuals, is scattered throughout the section. Rutile is present as
microscopic hair-like inclusions in the quartz and rarely as isolated grains. Sphene
grains are amongst the rarest of the accessory constituents.
A Rosiwal determination of the approximate mineral composition by volume
gave :
* “ Mineralogical Notes,” Trans. Roy. Soc. S. Aust., vol. xxxi, 1907, p. 119.
{ Note that in a granular rock the average absolute diameter of the grains is about twice that
obtained by averaging the diameters observed in the microscope slide.
FROM THE MAINLAND OF SOUTH VICTORIA LAND
A chemical analysis made by A. B. Walkom, B.Sc., and G. J. Burrows, B.Sc., resulted
as follows :
A comparison of the norm and mode is of interest.
Quartz .
Felspar
Mica
Garnet .
Apatite
Sphene, Leucoxene
si0,
TiO,
INO 6
Fe,0, .
FeO
MnO
MgO
CaO
Na,.O
KeO a
H,O+ .
H,O- .
1240)
Co,
Total
Per cent.
54:0
42°0
2-5
0-5
0:5
0:5
100-0
76-01
0-31
13-29
0-52
1-75
0-01
0-60
0-72
3°33
2-63
0-25
0-27
0-37
0-06
100-12
weight composition calculated from the volume composition already noted.
THE NORM
(Percentage weight)
Quartz . A 3 ; 44-46
Orthoclase 15-56
Albite . 28-30
Anorthite 0-28
Corundum , : 4-90
Hypersthene . : : 3-74
Ilmenite , 0-61
Magnetite 0-70
Apatite 0-93
Water . 0-52
100-0
These figures correspond with those of the chemical composition of an extremely acid
granite.
Chemico-mineralogical Classification :
(Alsbachose.)
This is distinctly more acid than the massive granite outcrops of South Victoria
Land. Concentration of the quartz grains and the elimination of soluble alkali and
iron would be expected to attend any sedimentation process to a more or less marked
extent.
THE MODE
(Percentage weight)
Quartz . : : ; 54-2
Felspar . : : : 41-0
Mica. j ; : 2:8
Garnet . : : : 0-7
Apatite . : : : 0-6
Leucoxene, Sphene, etc. . 0-7
100-0
Class 1, Order 3, Rang 2, Subrang
The latter is the percentage
208 PETROLOGY OF ROCK COLLECTIONS
The abundance of microcline felspar, the strain features, and the presence of garnet
indicate an origin from acid igneous rocks metamorphosed prior to the period of sedi-
mentation represented by the arkose. The character of the garnet and its association
with the felspar is clear evidence that the garnet was developed secondarily in the
original gneiss at the expense of anorthite molecules of the felspars. The most important
contributor to the newer sediment, it appears, was an acid garnetiferous gneiss. The
unsorted character of the mineral constituents—the angular nature of the grains—and
the freedom from chemical decomposition are, I believe, evidence that disintegration
and deposition took place under semiglacial conditions. In small hand-specimens,
rocks of this character are difficult to distinguish from some dynamometamorphosed
granites, but I feel satisfied that there is no confusion in this case. Thick deposits
of a similar nature are regularly met with amongst the beds associated with glacial
horizons in South Australia.
Other specimens from the Upper Glacial Depot, Beadmore Glacier, not otherwise
differing from this arkose type, carry abundant carbonaceous material along certain of
the bedding planes. Thus, finally, carbonaceous shale and grits are arrived at and
indeed coal* itself is amongst the specimens associated therewith.
Though this arkose appears to be the prevailing psammite of the Beadmore Glacier
area there are, also, specimens more nearly approaching normal quartzites. One of
these from the Cloudmaker is a buff-coloured felspathic quartzite. Distinct and regular
bedding lines are marked out by iron-ore zones alternating with bands free from iron
ores. In it, current bedding is well shown.
PELITES
Examples of this class are rare amongst the collections. On the magnetic pole
journey only a few specimens of limestone and a few chips of slate were met with ;
amongst the former is an interesting erratic from Dunlop Island, the latter are mostly
from amongst the moraines in the vicinity of Mounts Larsen and Nansen. From the
Ferrar Glacier area Priestley collected fragments of a dense calcareous slate from the
upper moraines. This material in character recalls the non-fossiliferous Cambrian
slates of South Australia, with which I am familiar.
In the Beardmore Glacier collection are a number of examples of slates and phyllites.
It is quite likely that all are of one age, as indicated by a specimen which clearly shows
that its phyllitic characters have been induced by the infiltration of mineral-bearing
waters along a fissure now occupied by vein quartz. Specimens from the vicinity of
the Cloudmaker range from a faintly purple-coloured slate to light grey or greenish
coloured phyllites in which abundant sericite has been developed ; minute particles
of pyrite are also frequent. In one case the phyllite is spotted and contains a pyrite
crystal 1 cm. square. The evidence of the quartz vein and the general metamorphism
of the slates argues a date of deposition antecedent to an igneous intrusive period
in the local geological history. It is unlikely that these sediments are newer than the
Paleozoic. Associated with these slates and phyllites are calcareous types and even
pure limestones.
* The coal strata are described elsewhere in these volumes.
+ The limestones are elsewhere specially described by Professor E. W. Skeats.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 209
THE IGNEOUS ROCKS
Ferrar and Prior have described a large series of igneous rocks from South Victoria
Land. Most prominent amongst these are granites, mostly very ancient, dolerites
of intermediate age, and a recent alkali series of intermediate and basic rocks. None
of the latter occur in situ on the mainland in the region within the scope of these col-
lections. Erratic blocks are, however, frequent. Ferrar distinguishes an older and a
younger granite. The older granites are grey and intrude an ancient metamorphic
series of gneisses and schists. The younger granites are pink in colour, and according
to Ferrar intrude the dolerite sills which are themselves younger than the Beacon
Sandstone. More information on the subject of the relative ages of the pink granite
and the dolerite is desirable, for our observations have shown that there do exist grey
granites of the same age as some pink granites.
Ferrar also met with diorites, syenites, gabbros, and lamprophyric, aplitic, and
pegmatitic rocks.
For convenience I have recognised the following groups:
The Granites and their associated Dyke Rocks. The latter include porphyrites,
aplites, pegmatites, and lamprophyres. Granites of several ages are recognised.
The Diorites. These doubtless correspond in age with some of the granites.
The Gabbros. Most of those classified under this heading are believed to be older
than the “ dolerites”’ ; others may be special phases of the latter.
The Dolerites. Included herein are a variety of closely similar types all of the
same period, intrusive in the Beacon Sandstone formation, and therefore comparatively
young. They appear to belong to the one great intrusive act illustrated by the dolerites
of Tasmania. They range over an enormous area of Antarctica.*
The Recent Volcanic Series. Rocks of this series are of tertiary and recent age and
are exemplified in the extravasations of Mount Erebus. It is doubtful whether any
outpourings of this class have taken place on the mainland proper within the area
embraced by these collections.
THE GRANITES AND ASSOCIATED DYKE ROCKS
Granites and their dynamometamorphic equivalents form a large part of the exposed
areas, and consequently the collections are rich therein.
The majority of the specimens collected are coarse-grained and porphyritic with large
pink orthoclase crystals. Very large outcrops of this granite are known to occur between
75° 50'S. lat. to 78° 8. lat. It is probable, however, that the areas occupied by grey
granites predominate. Petrological comparisons and certain field evidence indicates
a relationship between the pink granites and certain of the grey granites. This re-
lationship is closer than is likely to be the case if they belong to two widely separated
periods. This, however, appears to be the case with others of the grey granites as
indicated by Ferrar’s field evidence.
In any case it is certain that granites older than the pink felspar granites exist,
for some of the granite-gneisses are plainly of such antiquity. It is significant that
of the arkoses, so frequent amongst the sedimentary rocks, none have yet been met
containing pink felspars.
* These are described in detail elsewhere in this volume by W. N. Benson, B.Se.
y+ Examples of such rocks have been brought to light by the recent Scott Expedition.—D. M.,
1916. tX Loe. cit., p. 36.
210 PETROLOGY OF ROCK COLLECTIONS
Accompanying these granites are frequent dyke rocks, including granite porphyrites,
aplites, pegmatites, and lamprophyres.
In regard to the metamorphic action of the granites upon the intruded rocks, little
exact information is available. It is more than likely, however, that the majority
of the schists and gneisses, so abundantly represented in our collections, originated in
connection with the intrusion of the granites.
It seems sufficiently clear at least that the great marble and calc-silicate belt owes
its present condition to the influence of these intrusions upon original limestones.
THE PINK GRANITES
Chiefest and best known is the coarse-grained pink granite typically developed at Cape
Irizar. The outcrop there protrudes from the ice over a length of half a mile or more.
Other examples were met with in the Ferrar Glacier locality and at intervals along
the coast. Dr. Prior has described this and allied granites occuring in situ at the
Ferrar Glacier,* and at Cape Adare.t Professor David, Mr. Smeeth, and Mr. Schofield
have described granite erratics collected by Mr. Borchgrevick at Cape Adare.t
The textures vary somewhat in the different outcrops. At Cape Ivizar the Shap
Fell type is general, whilst certain of the specimens from the Ferrar Glacier are textured
hke the Rapakiwi granite. Very similar granites are met with intruding the Cambrian
sediments of South Australia; e.g. at Murray Bridge and Granite Island.
The pink coloration is due to the prevailing tint of the abundant orthoclase felspars.
The depth of colour is affected somewhat by exposure, for the outcrops are generally
pinker than freshly broken faces. The tinting is by no means evenly distributed, but
even in small exposures varies from a deep red to practically white. At Cape Ivizar
a fracture zone in the granite, up which a lamprophyric magma ascended, has assumed
a deep red colour, due, obviously, to secondary causes. In general the deeper coloured
the rock the greater is the content of accessory minerals.
All the pink granites are hornblendic ; with the hornblende is usually some biotite
also. In this way they differ from the grey granites, which contain but little or no
hornblende.
HORNBLENDE-BIOTITE GRANITE ; CAPE IRizar. (Plate I, Fig. 4)
Most conspicuous in the hand-specimen are abundant porphyritic rectangular pink
orthoclase crystals twinned after the Carlsbad law: these are embedded in an even
granular base containing a little orthoclase, much plagioclase, abundance of quartz
blebs, conspicuous hornblendes, and a varying quantity of biotite. The chief variants
are the hornblende and biotite. In particular parts of the outcrop the one may increase
in quantity almost to the exclusion of the other.
Microscopic Characters. (Figs. 4 and 5, Plate III.) The texture is porphyritic granular.
Large idiomorphic orthoclases distributed through a hypidiomorphic granular base con-
sisting of plagioclase, orthoclase, quartz, hornblende, mica, and accessory minerals.
Quartz in subangular grains often showing strain effects. The usual inclusions are
present. It is a later crystallisation than the plagioclase, and appears to have ac-
companied the latest phase of orthoclase separation. Orthoclase. Present in two forms.
The porphyritic individuals measure up to 2°5 cm. diameter and are twinned after the
Carlsbad law. Idiomorphic plagioclases are often included in them. The small
orthoclases in the ground-mass and certain additions to the porphyritic individuals
* Loc. cit. p. 125.
+ “* Southern Cross’ Collections,” Brit. Mus. Nat. Hist. publication, 1902, p. 322.
ft Proc. Roy. Soc. N.S.W., vol. xxix, p. 481 (1895).
FROM THE MAINLAND OF SOUTH VICTORIA LAND 211
represent the latest separations of orthoclastic material. There has probably been no
lapse of time between these successive modes of separation, the variation being merely
consequent upon the changing physical-chemical conditions existing in the magma.
Microperthitic intergrowths are common. Some part of the orthoclase showing
mottled markings under crossed nicols appears to be soda orthoclase. Generally
speaking the mineral is very fresh. Dusty change-products become prominent in the
redder felspars of certain outcrops where metamorphosing external agencies, referred
to later, exerted an influence. Plagioclase, chiefly oligoclase but occasionally as basic
as andesine. Twinning is usually after the albite law only, though occasionally noted
compounded with the Carlsbad type. It is always more dusty than the orthoclase.
Amongst the secondary minerals white micaceous flakes are recognisable. The
plagioclase has crystallised earlier than the quartz and orthoclase. The mica is a
biotite, pleochroic (yellows and browns). The lamine are often slightly bent. The
hornblende occurs in irregular prisms. At a hasty glance it is not easily distinguished
from the biotite. It is pleochroic from light yellow to dark green. Chloritic decom-
position products are sometimes observed. Magnetite in irregular grains only rarely
seen. Sphene is still rarer and observed almost always adhering to magnetite grains.
Apatite is very rare: it appears always in the tiniest crystals adhering to magnetite
or embedded in the biotite. Zircon appears to be more frequent in some specimens
than others. It is seen as minute grey crystals almost always embedded in the biotite
mica and surrounded by pleochroic haloes. Allanite is by far the commonest of the
accessory minerals appearing in nearly all the granites in our collections. In slides
from this particular rock grains 5 mm. diameter were met with. It is generally
associated with biotite and is always idiomorphic. It is of a brown colour, slightly
pleochroic and distinctly zoned. It is weakly doubly refracting and has high refractive
indices.
An approximate Rosiwal mineral analysis gave :
Mover
Quartz ; : : : , ‘ ; . 29°5
Orthoclase, including soda orthoclase _.. : «320
Microcline. : ‘ , : 3 i petro
Plagioclase, chiefly oligoclase . ‘ ; : = 225:0
Biotite : , : : : : ¢ a aw)
Hornblende ; : : : : 5 = 22:0
Accessories. : : ‘ ; ; : S03
The following is a chemical analysis of a fresh sample made by A. B. Walkom, B.Sc. :
SiOnn ; ; Si
AO, 5 : i - 0-25
ar TED Wy eae: ae COMPOSITION OF THE NORM
FeO : ; : ; ‘ 2:10 Quartz . : ; . 27-60
MnO . ‘ : , 0-04 Orthoclase . : : 27-80
MgO . ‘ ‘ n 0-29 Albite . 5 : 2 33:01
CaO Cg. 5 ; ; 0-84 Anorthite 3 5 A 4-17
Na,O . é : : 3:88 Corundum . é : 2-14
ISAO g : : : 4-72 Hypersthene . : : 3-74
H,0+ . j é : 0-35 Ilmenite : : 5 0-46
H,O- . : : : 0-15 Magnetite . : : 0-93
IPO, : 6 . trace =
COs 3 : ‘ 0-09 99°85
100:36
II 2H
212 PETROLOGY OF ROCK COLLECTIONS
Chemico-mineralogical Classification : Class 1, Order 4, Rang 1, Subrang 3 (Liparose).
The dyke-rock “following” includes granite porphyries, aplitic pegmatite, and ker-
santite. These are fully described in a later section. Metamorphism affecting this
rock is also referred to under the general subject of metamorphism.
Similar granites are to be met with at intervals between McMurdo Sound and
Mount Nansen. A red granite is observed extensively exposed on the mountain scarps
to the north-west of Granite Harbour. A whale-backed promontory (practically an
island) between Gregory Point and Ross Cape is composed entirely of this rock and
its dyke followmg. At other points erratic specimens were met. Certain outcrops
of a grey granite are texturally similar to the pink type, and it appears that they are
but variations of it. The grey granites in the neighbourhood of Mount Larsen are to
be mentioned in this connection.
Dr. Prior has already dealt with the pink granitic rocks of the Ferrar Glacier region.
Priestley’s collection contains abundant specimens also, one from a moraine in the East
Fork of the Ferrar Glacier proves to be identical with that already described; the
others are more in the nature of granite porphyries and descriptions will appear later.
THE GREY GRANITES
In the present state of our lack of knowledge concerning the field relations of these
rocks, the only other obvious subdivision into which we can split the granites is the
group of grey granites.
Sufficient has already been said to make it clear that these do not all belong to one
period of igneous activity ; furthermore, it seems clear that some of the grey granites
are closely connected with the pink granite already described. Such is the grey granite,
to be referred to immediately, occurring in situ to the south-east of Mount Larsen. A
comparison of the analyses shows the kindred characters of these rocks. The difference
lies mainly in increased proportion of plagioclase in the Mount Larsen rock. <A
quartz porphyry dyke which crosses the grey granite has a chemical composition
almost that of the pink granite, being richer in potash felspar than the parent grey
granite.
Evidence culled from observations relating to field occurrence, and especially
chemical composition in the differentiation sequence, suggests that much of the
original granitic magma has solidified as a more highly biotitic and plagioclastic grey
granite, followed by the separation of an orthoclastic hornblendic magma solidifying
as a pink granite occupying subsidiary bosses and dykes.
In this connection the Mount Larsen grey granite is specially worthy of study.
BioTITE GRANITE FROM NEAR Mount Larsen. (Fig. 6, Plate I)
Granite im situ at the foot of the Backstairs Passage Glacier, the sharp ascent to the
Larsen Glacier. A ridge composed of broken masses of this granite extends for a distance
of several hundred yards. In the hand-specimen it appears as an even fine-grained
light grey granite. Quartz, plagioclase, and biotite are the obvious constituents. This
rock is quite different in appearance to the Cape Inizar granite ; most noticeable is the
want of orthoclase.
Mvcroscopic Characters. The grain size in the slide averages 1°5 mm. diameter. The
texture is hypidiomorphic granular.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 213
Quartz in regular allotriomorphic grains. It is one of the last products of crystalli-
sation. Strain shadows are universal. Orthoclase is present only in very small quantities
as compared with the plagioclase. It usually shows the faint strize of anorthoclase.
Plagioclase is very abundant, and is distinguished by the fine lamelle of the albite
twin; Carlsbad twins are also rather frequent. The plagioclase crystals are hypidio-
morphic and occasionally idiomorphic. Both orthoclase and plagioclase are compara-
tively fresh. Bvotite is abundant ; pleochroism light yellow to deep yellowish-green.
Allanite occurs in stout prisms embedded in the biotite. It is of a yellowish-brown
colour and well zoned. Apatite in colourless stout prisms is also frequently observed
enclosed in the biotites.
The chemical analysis determined by A. B. Walkom, B.Sc., is as follows :
SiO, . : : : 69-85
TOs. : 3 0:36
AlOxe 3 : ; 15-35 COMPOSITION OF THE NORM
Fe,0; . : . . 0-40 Quartz . ; : > ol-86
FeO. oy asp es 3 3-88 Orthoclase . . . 17-24
MgO. - . «052 Albite . « . « 26:20
CaO. : : : 2-94 Anorthite ‘ ; P 10-84
K,0_ . : . : 2-87 Corundum . ; F 3-06
Na,O . : : : 3-13 Hypersthene . ‘ ‘ 7-50
H,O+ . : : : 0-24 Magnetite . E : 0-70
H,O- . . : : 0-03 Ilmenite : ‘ : 0-61
om . : : . Hee Apatite . ‘ F ; 1-34
n . 5 ¢ . ae st
1240); = ‘ ; : 0-50 99°35
100-14
Chemico-mineralogical Classification : Class 1, Sub-class 1, Order 4, Rang 3,
Subrang 3 (Amuatose).
An even-grained grey granite collected as an erratic specimen from Dry Valley,
New Harbour, is very similar to that from Mount Larsen.
FINE-GRAINED GRANITE; BEARDMORE GLACIER. (Fig. 7, Plate I)
A fine even-grained light grey granite composed of quartz, white felspar, and fine
fragments of biotite from the Lower Glacier Depot, Beardmore Glacier.
Microscopie Characters (Fig. 3, Plate III). Allotriomorphic granular texture. The
minerals are chiefly quartz, orthoclase (microline and anorthoclase), plagioclase (oligo-
clase chiefly), biotite, apatite, and magnetite.
The quartz is present as clear grains of irregular or rounded boundaries; these
seldom exceed 1 mm. diameter. Rounded blebs of quartz (quartz de corrosion) are
frequently embedded in the microcline. The orthoclase is chiefly microcline and
anorthoclase though clear simple-twinned orthoclase is present. Gitter structure is
beautifully shown in the microcline, which is always fresh. Plagioclase is generally
dusty with change products which include flakes of secondary white mica. Measure-
ments of the optical constants show the range to be between acid andesine and acid
oligoclase. Biotite, pleochroic in green and yellow, is present in very small amount
only ; a change to chlorite is observable. uscovite in small quantity is present also.
Scattered grains of magnetite and tiny rods of apatite complete the list of constituents.
214 PETROLOGY OF ROCK COLLECTIONS
The approximate composition of the mode as determined by the Rosiwal method
is as follows :
Per cent.
Quartz . ‘ . : : A : 26
Orthoclase F , . : 5 ‘ 12
Microcline and anorthoclase 5 ‘ 39
Plagioclase : ¢ 2 5 : : 19
Mica ‘ 5 3 3 ‘ 3 4
100
Stress is indicated by the optical characters of the constituents. It closely resembles
certain Pre-Cambrian granites of South Australia and is lkely to prove of considerable
antiquity. The arkose already described from this locality contams an abundance
of microcline likely to have been derived from this and similar rocks.
From this locality was got a specimen of a like granite stained yellowish due to
weathering.
Porpnyritic BioTirE GRANITE; BEARDMORE GLACIER. (Fig. 5, Plate 1)
A grey granite from the Lower Glacier Depot. It contains porphyritic white ortho-
clase crystals 2°5 cm. diameter twinned after the Carlsbad law. The texture of this
rock resembles that of some of the porphyritic pink felspar granites of the Cape Irizar
type.
: The orthoclase, largely anorthoclase and microcline, is almost exclusively comprised
in the porphyritic crystals. The plagioclase is an acid andesine and oligoclase and
constitutes a large part of the finer material of the rock. Biotite is present, pleochroic
from light yellow to deep brown. Associated with the biotite is a little sphene and
abundant tiny prisms of apatite.
There is no evidence opposed to a possible relationship of this granite with those
described from more northerly areas.
From the same locality comes a still coarser porphyritic granite similar in other
respects. This bears distinctly pegmatitic characters. One of the large orthoclases
contains scattered quartz fragments in a semi-graphic arrangement. Coarse black
biotite flakes reach 5 cm. diameter. Embedded in the biotite in one place is a red
brown crystal of sphene 3 mm. diameter.
A grey porphyritic granite very similar to the local pink variety is met with in the
form of erratics at Cape Irizar and at the rocky cape a few miles to the south. These
all contain sphene. In a more even-grained variety allanite is prominent, pleochroic
(light yellow to red-brown) and twinned.
Grey granites are described by Prior and Ferrar as occupying large areas in the
Ferrar Glacier region, at Granite Harbour, and at Cape Adare. Frequent erratics of
more or less metamorphosed grey granites were noted by us along the coast-lie. We
came upon extensive outcrops of such at Cape Roberts, Cape Ross, Depot Island, and
in the Mount Larsen neighbourhood. Lamprophyric dykes and inclusions are frequent
amongst them.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 215
THE GRANITE PORPHYRIES
A notable example of this class is that occurring 7n situ at the western end of the Kukri
Hills, Ferrar Glacier. There is little doubt but that this is a dyke rock of the Cape
Trizar granite magma. It is an intermediate stage between the granites already
described and the quartz and felspar porphyries to follow. As porphyritic ingredients
it contains large pink orthoclase crystals 2-5 cm. long, less noticeable smaller white
oligoclases, small idiomorphic quartz crystals, and abundance of hornblende prisms.
These coarse crystallisations are scattered through a uniform even fine-grained pink
base composed of granular quartz, orthoclase, and plagioclase, with some biotite and
subordinate hornblende.
Other specimens nearly related thereto, representing variations in the solidification
of the magma, occurring under conditions ranging from those which lead to the
development of typical granite, and those characterising the solidification stages of
porphyritic aplites, are represented.
One of these from the Knob Head Moraine carries a phenocryst of orthoclase 7 cm.
inlength. This crystal and even the smaller individuals of ground-mass show indications
of dynamic force by fracture. Occupying a fissure in the orthoclase is a vein of
hornblende.
Another example from the Stranded Moraines, East Fork, Ferrar Glacier, shows
hornblende prisms 1 cm. long, and these enclose flakes of biotite.
In another specimen from this latter locality the hornblendes contain poikilitically
included felspar.
THE FELSPAR AND QUARTZ PORPHYRIES *
QuARTZ PORPHYRY FROM NEAR Mount LARSEN
Quartz Porphyry occurring in situ as an injection in the even granular granite already
described outcropping to the south-east of Mount Larsen (Fig. 3, Plate II).
The hand-specomen shows idiomorphic crystals of quartz and faintly pink orthoclase
distributed through a dense grey base. The orthoclase crystals reach a length of
7 mm. and éhe quartz individuals a diameter of 4mm. Occasional planes of fracture
traversing the massive rock are filled with pistacio-green epidote. These veins are
never more than 2 mm. across.
The mucroscopic examination shows the presence of some plagioclase, biotite,
magnetite, and sphene, in addition to the above. Quartz phenocrysts of idiomorphie
form are prominent. The hexagonal bipyramids, which are perfect in form, reach a
diameter of 4 mm. The orthoclase is very fresh. Carlsbad twins are combined with
delicate cross twin-strize indicating the felspar to be a soda variety of the anorthoclase
type. In one case a Baveno twin makes its appearance. Plagioclase crystals are present
though much less frequent and smaller than the orthoclase. Extinction determinations
indicate them to have the composition of oligoclase. They are yellowish to greenish-
yellow in colour, due to secondary alteration, which is much more evident than in the
case of the orthoclase. An idiomorphic oligoclase individual was noted embedded in
an anorthoclase. Birotite as irregular fragments showing strong absorption, pleochroic
in yellows and greens. Magnetite : a few idiomorphic grains. Sphene of grey colour
in scattered irregular aggregates, sometimes encased in the mica. Apatite as minute
prisms noted only very rarely. Allanite. Rare scattered prisms are met with floating
* Rocks of this class from Cape Adare are described by Dr. Prior, loc. cit., p. 324.
216 PETROLOGY OF ROCK COLLECTIONS
freely in the base. The base presents a very even appearance under the microscope.
It is composed of uniform grains -025 mm. diameter. This fine granular material is
observed to consist of clear quartz and slightly dusty felspar, the latter apparently
orthoclase as its refractive index is below that of Canada balsam. This is not the usual
devitrified base typical of the quartz porphyries, but approaches the character of
granite aplite. The analysis further corroborates this observation. It is clear that
this porphyry is a separation from the granite in which it is found.
The chemical composition as determined by A. B. Walkom, B.Sc., is as follows :
Si0, . . : - 73°55
HOF : : x 0-21
INO . : é 13-70 THE NORM
Fe,0; . . . . 0-24 Quartz . ‘ ‘ 5 alert
HeQU ay Na eee | 2106 Orthoclae . . . 2613
CaO) Se) Peed es 10:02 Albite . =. 8 7230:39
MeO = 0:26 Anorthite . . . 4:45
Na,O . : . : 3:59 Corundum . 5 ; 1-33
K,0 . : : . 4-46 Hypersthene . 5 : 4-43
HO Oi “sean 60:36 Ilmenite lene, 4046
aor : : : : SEL Magnetite r : 0-23
2 . . . . sl ———
MnO . ‘ 4 : 0-05 99-16
HOR + d : . Not det.
99-82
Chemico-mineralogical Classification: Class 1, Sub-class 1, Order 4, Rang 2,
Sub-Rang 3 (Toscanose).
Felspar Porphyry. Black porphyry from a rocky cape about 8 miles south of
Cape Inizar. In one specimen the porphyry is conjoined with a grey biotite granite
which it has evidently intruded (Fig. 4, Plate II).
This granite is identical in character to that described as occurring in situ south-
east of Mount Larsen. The porphyry, though strikingly different in outward
appearance, is, therefore, closely related to that just described. In the hand-specimen
small white and pinkish felspars appear distributed through a black cryptocrystalline
base.
Under the microscope the felspar is noted to be orthoclase twinned after the Carlsbad
law, and rarely acid plagioclase. A few grains of faintly coloured epidote are present
in close connection with the felspars, obviously an alteration product. Bvotite is
present as occasional flakes, yellowish to greenish-yellow in colour. More rarely grains
of wmenite are met with. The base is a devitrified glass, partly doubly refracting but
unidentifiable.
Orthoclase Porphyry. A rock (Fig. 1, Plate II) from the Stranded Moraines, East
Fork, Ferrar Glacier, is best catalogued here. It differs considerably from other
specimens, but the character of the orthoclase phenocrysts suggests that it, also, belongs
to the granite following. It consists of large white orthoclase crystals, about 1-5 cm.
diameter, twinned after the Carlsbad law; these are scattered through a fine dark-
coloured base. The base contains acid plagioclase, quartz, a little hornblende and
unresolvable devitrified greyish interstitial matter.
Red Felspar Porphyry. An erratic specimen from Cape Irizar. Studded through
the jasperoid base are occasional white felspars.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 217
Pink and Grey Porphyries from the Stranded Moraines, Kast Fork of the Ferrar
Glacier. The porphyritic constituents are white or pinkish felspar, quartz, and
frequently mica. There is a marked orientation of the felspars and flow is further
indicated by parallel dark streaks. These rocks are very dense and of the halleflinta
type, and may possibly be of much older age than those described earlier. They very
closely resemble certain Pre-Cambrian porphyries of Southern Australia. In the case of
other porphyries from the East Fork of the Ferrar Glacier, the bases are microscopically
crystalline and in other respects they resemble the aplitic porphyries of the Cape Irizar
granite following.
Another interesting orthoclase porphyry (Fig. 2, Plate II) is a grey hornblendic
variety occurring 7m situ at the Kukri Hills, Ferrar Glacier. This is rather more basic
than usual as it contains much plagioclase. It is rendered remarkable on account of
the white orthoclase crystals 12 mm. in length, studded throughout the hand-specimens.
The ultimate base consists of quartz and orthoclase, which frequently exhibit a micro-
pegmatitic structure.
THE APLITIC GRANITE PORPHYRIES
There are now to be considered a large number of specimens illustrating granite
porphyries in which an aplitic base is the most conspicuous part. They always form
part of the granite masses but are usually of small size and very irregular in shape. In
the more regular dyke-like occurrences, the porphyritic constituents diminish in bulk
and typical aplites are arrived at. The aplitic condition is perfect when the rock is
an even-grained panidiomorphic mixture of quartz and orthoclase with inconspicuous
amounts of accessory minerals. The base is either grey or pink in colour ; as a rule
the more aplitic types are the pinker in colour.
APLITIC GRANITE PoRPHYRY ; CAPE [RIZAR
A typical example of this aplitic granite porphyry occurs at Cape Ivizar, about a
quarter of a mile west of the extreme point. There, there are two parallel outcrops
emerging from amongst the granite ; the junctions are unfortunately obscured. In
the hand-specimen it appears grey, with rather large pieces of porphyritic orthoclase
as much as 9 mm. in diameter.
Hornblende prisms up to 6 mm. diameter are not infrequent. Aggregates of varying
size consisting of porphyritic quartz, felspar, mica, and even hornblende are scattered
through the finer base.
In the microscopic section (Figs. 6 and 8, Plate III) porphyritic orthoclase, anortho-
clase, oligoclase, hornblende, and quartz are distinguished. The hornblende and some of
the felspars are in sharply defined crystals, whilst other minerals are corroded. Horn-
blende is plentiful, pleochroic in light yellow, yellowish-green, and blue-green. Viewed
in ordinary light it is of a blue tint. Some are true reibeckite whilst others appear to
be intermediate between the latter and common hornblende. The base is a fine
granular mixture of quartz and orthoclase and some oligoclase. The grain size averages
0-15 mm. The felspar is hypidiomorphic or idiomorphic in form. Graphic inter-
growths of the quartz and felspar are often present in this class of rock, but are not
marked in this particular outcrop. Allanite: several pieces noted. There are a few
grains of amenite, leucoxene, and of pyrites.
The granite, near the junction of this aplitic porphyry, contains a larger proportion
of hornblende, entirely replacing the biotite. Zoning is noticeable in some of the
plagioclase crystals.
218 PETROLOGY OF ROCK COLLECTIONS
The chemical composition as determined by A. B. Walkom, B.Sc., is as follows :
SiO, . : F . 713-64
TiO, . : p } 0-33 COMPOSITION OF THE NORM
INO ‘ é ; 13-95 Quartz . : , . 380-24
Fe,0, . : ‘ j 0:90 Orthoclase . i ; 16-12
FeO. : : : 1-40 Albite . : j . 43-49
MnO . : , : trace Anorthite : : : 4-73
MgO . é : é 0-30 Corundum c : 0-82
CaO... : : : 0-96 Hypersthene . : : 1-99)
K,0 . : ° : 2-73 Magnetite . c c 1:39
Na,O . ‘ ‘ : 5-17 Ilmenite 3 : : 0-61
HeOe hte ee © 047 Water. . . . 0-63
H,O- . , - : 0-16
POs): ‘ : . not det. 100-02
99-99
Chemico-mineralogical Classification: Class 1, Order 4, Rang 2, Sub-rang 4 (Lassenose).
Several nearly spherical masses, only a few inches in diameter, of this type of rock
were observed embedded in the coarse crystallised granite of the main outcrop at Cape
Irizar. In this again the hornblende is abundant and some of distinctly alkaline type.
Allanite and pyrites are also frequent.
In another specimen from Cape Irizar the hornblendes are sometimes surrounded
by an outer zone of an irregular greenish-blue colour. In this case the porphyritic
crystals are all plagioclase.
A further specimen of the grey rock occurring as an erratic at Cape Inizar yields
additional information. In this the hornblende needles are more distinct. Porphyritic
idiomorphic plagioclase crystals are also a feature of the rock.
Under the microscope (Fig. 7, Plate III) the plagioclase phenocrysts are noted to
be well zoned, ranging from an acid labradorite within to a basic oligoclase without.
They are much changed to dusty doubly refracting aggregates, so that it is difficult to
distinguish exactly the relative proportions of plagioclase and orthoclase. Quartz is
abundant but present only as small particles amongst the orthoclase felspars of the
base. The hornblendes areidiomorphic and zoned. The usual pleochroism is red-brown,
greenish-yellow, light yellow. The extinction angle isnearly straight. The periphery
of the hornblendes appear to be undergoing a chloritic change. There are grains of
magnetite frequently with a little leucoxene attached. The base is composed of a fine-
grained mass of even-sized idiomorphic felspars with some quartz. Several cracks
traversing the specimen are occupied by yellowish epzdote.
There are a number of specimens collected as erratics similar to these, but of a
general pink tint. A typical example is the following from Cape Irizar. The hand-
specimen is of a pink colour and shows abundant porphyritic felspars and some finer
hornblende. In the section it is apparent that the porphyritic felspars are
almost all plagioclase which are changing with the production of faintly coloured
epidote. There are some orthoclase crystals twinned after the Carlsbad law. The
hornblende is pleochroic from light yellow to bluish-green to red-brown. In the
case of one crystal a bluish-green border was observed on a red-brown basal
section. Grains of magnetite and sphene are obvious. ‘The base is principally quartz
and orthoclase in eutectic, largely graphic, arrangement ; there is here also a little acid
plagioclase.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 219
Another specimen from the same locality contains a cavity occupied by calcite.
The walls of the cavity are quartz and felspar in drusy relief. The felspar is much
altered, so much so that, in the case of some squarish sections occupied by secondary
minerals, it is not certain that they may not have been nephelines. In all these rocks
no stainable products were discovered, and therefore this suggestion of nepheline
cannot bear much weight.
Aplitic granite porphyries, both pink and grey, are met with in the Ferrar Glacier
collection. These are notably from the moraines of the East Fork of the Ferrar Glacier
and elsewhere in the neighbourhood of the Kukri Hills.
THE APLITES
As already stated the aplitic granite porphyries are a transition stage between the
hypidiomorphic-granular granite and the panidiomorphic fine-granular aplite. Between
the aplitic granite prophyries and the true aplites are porphyritic aplites of the
alsbachite type. In the typical aplites the chief components are orthoclase and quartz,
and the texture expresses eutectic composition. Numerous specimens were found as
erratics in the vicinity of the granite outcrops. Of these the following two from Cape
Irizar are worthy of description. One of these is of an almost white colour relieved
by black specks of biotite. Smali porphyritic crystals of anorthoclase are studded
sparingly through the finer grained base. Under the microscope the base is seen to be
granular and poikilitic patches are frequent. The quariz grains are surrounded by
orthoclase arranged with great regularity. The biotite shows lght yellowish and
greenish tints.
The other example is of a light pink colour. The texture is very fine and even.
Under the microscope (Fig. 9, Plate III) small porphyritic oligoclase crystals appear at
intervals and are invariably surrounded by radial-graphic quartz and orthoclase. The
remainder of the section consists of granular quartz and orthoclase with occasional but
rare porphyritic orthoclases of a late period of crystallisation. Ferromagnesian minerals
are almost absent. Grains of zdmenite, and rarely small yellowish grains appearing to
be epidote are present.
In this rock, obviously, a sprinkling of small plagioclase crystals was the first act
in crystallisation.
THE PEGMATITES
Pegmatite veins in connection with the pink granite appear to be of rare occurrence
for none were met with im situ. Examples of coarse pegmatites occur amongst our
collections of erratics.
Ferrar mentions quartzose, felspathic, and micaceous veins in the grey granites of
the McMurdo Sound region. Priestley’s collection also contains coarse pegmatitic
granite and vein quartz. In some cases these are to be seen traversing a grey
ranite.
i The outcrops of the gneiss and schist series are never free from pegmatite veins,
and undoubtedly the majority of the erratic specimens are derived therefrom. Such
a one is a coarse quartz-microcline rock from the Stranded Moraines ; this also carries
some muscovite and frequent pink garnets, the latter up to 3 mm. diameter.
The gneiss at Cape Roberts is rich in coarse-crystallised veins, usually quartz and
felspar, at other times quartz, felspar, and biotite. Amongst these, felspars 23 cm. in
length and much graphic quartz and orthoclase were noted.
At Cape Bernacchi, and at Marble Point several miles to the north of the latter, an
ancient sedimentary series, conspicuous amongst the members of which is a thick
marble formation, is crossed by pegmatitic formations. Amongst these is a quartz-
iI 21
220 PETROLOGY OF ROCK COLLECTIONS
felspar-mica rock, sometimes containing much black tourmaline ; quartz veins carrying
pyrites ; also more basic formations containing abundant biotite and hypersthene.
From the Beardmore Glacier are specimens of reef quartz and coarse quartz-
microcline-biotite rock.
THE LAMPROPHYRES
KERSANTITES (CAMPTONITIC)
Associated with the granites are frequent narrow basic dykes (Fig. 4, Plate IV).
That described at length herewith is a kersantite, but others appear to tend towards
camptonites and tinguaites. The dykes are usually irregular in length and narrow in
width. When as narrow veins they are very close textured, in part devitrified glasses.
In almost all cases a marginal zone, a few centimetres wide, appears to have solidified as
glass. Where the dykes are some feet in width, the central portions are occupied by
material in which the crystallisation is evident to the unaided eye. It is not unusual to
find a sprinkling of small porphyritic plagioclase crystals. At all times fragments of the
enclosing granite or of the minerals therefrom may be expected, partially corroded,
suspended in the dyke rock.
The lamprophyres are always very dark in colour, practically black. The weathered
surfaces often exhibit dark bluish and greenish tints. As it is more readily weathered
than the enclosing granite, it is usual to find the dykes occupying depressions in the
surface. On this account, also, lichens are more frequently noted adhering to its
surface than to the granite.
The effect of these intrusions upon the neighbouring granite is marked to the naked-
eye inspection by an increased depth of colour in the pink granite. The large orthoclase
crystals are converted to a bright red colour. Examined under the microscope the
changes are seen to lie chiefly in notable sericitisation of the felspar and chloritisation
of the hornblende and biotite. In addition the quartzes often appear smoky, and
there is generally present a larger content of accessory minerals. Slides of the granite
cut in close proximity to the contact show numerous planes of fracture approximately
parallel with the main line of fissure. These average not more than 0°75 mm. in width
and are occupied by the crushed and recemented constituents of the granite.
Specimens from different locations are found to vary very much in the freshness
of the constituents. In some uralisation, chloritisation, and serpentisation are far
advanced and the original characters of the more readily affected minerals entirely
obliterated.
KERSANTITE FROM CAPE [RIZAR
This is one of the denser types. In it minute plagioclase laths can be distinguished,
also frequent grains of strongly pleochroic (yellow to dark brown) hornblende. Grains
of ilmenite and pyrites are present. The base is very dense and may have partly
solidified as a glass. It is now pervaded with a chloritic alteration. The hornblendes
are also attacked by chloritisation.
Specimens from other portions of the same dyke throw more light upon the mineral
composition of this rock. There is a dominance of plagioclase (acid labradorite to
andesine) which is present both as small laths and larger porphyritic zoned crystals.
Carlsbad, albite, and pericline twins are present. Hornblende (usually basaltic) is
present in idiomorphic rods. Light-coloured pyroxene partly uralitised is present in
this dyke but seldom in others. Rarely flakes of biotite appear. Ilmenite, usually
leucoxenised, is always abundant, so also is apatite. The finer material of the base of
holocrystalline samples appears to contain some fine granular orthoclase. In these
cases particles of quartz are evenly distributed through the section.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 221
In a specimen from one portion of the dyke where the base appears to be a devitrified
glass, there appear numerous polygonal, nearly spherical, clear patches of aggregates of
a highly refracting colourless mineral suggesting change products of leucite. These
are as much as 0°25 mm. diameter.
An analysis made by A. B. Walkom, B.Sc., of the dense variety of this rock first
mentioned is as follows :
si0, . : : . 54-27
IO) : ‘ ‘ 1-33
Al,O; . : F - 19°23 COMPOSITION OF THE NORM
Heo ee pes 9 LOS @Qustizs 1% . : 1-92
FeO. . . : 8-29 Orthoclase . : . 15-01
MeOn = aye a Albite . ae 25-68
CaO : . . . 6-41 Anorthite ; : . 931-69
Na,O . . : . 3-05 Hypersthene . : . 21-84
K,0 . , . . 2-49 Magnetite . ‘ : 0-93
Or ee mo Oil Iimenite . . .. 2-48
ae 3 = - - 0-18 Eg Olt». : 5 ' 0-95
CO, : ‘ : ; 0-05 co 0-05
MnO . : ‘ . not det. :
ADs < ‘ j . not det. 100-50
100-54
Chemico-mineralogical Classification: Class 2, Order 5, Rang 3, Sub-rang 4 (Andose).
A comparison of this analysis with that of the granite shows a marked increase in
the basic constituents, lime and magnesia, and a concentration of soda as opposed to
potash. In the mineral components the fundamental difference lies in the elimination
of orthoclase with substitution of plagioclase. It is obviously a lamprophyric separation
from the granitic magma.
The character of some of the occurrences are suggestive of tinguaites, but in no
case have staining methods revealed the presence of any felspathoid. Furthermore,
the alkali content of the above analysis is too low to suspect the presence of fel-
spathoids.
These lamprophyres frequently resemble camptonites and it is probable that the
camptonites mentioned by Dr. Prior * are closely related to these intrusions. The
analysis of the rock type here described is, however, unlike that of the camptonites, for
it lies with the more acid lamprophyres.
As hornblende is the dominant coloured constituent in all the outcrops, the choice
lies with kersanite and spessartite. The low magnesium and iron content and
the high proportion of plagioclase felspar clearly indicate the rock analysed to be a
kersantite. As hornblende is present in quantity in all the outcrops, sometimes to the
exclusion of the biotite, they are more correctly described as hornblende kersantites.
Dr. Prior ¢ has described a kersantite from a dyke intersecting the ancient crystalline
limestone formation in the Ferrar Glacier region. This is an augite-biotite-kersantite
and differs somewhat in appearance from the dyke rocks commonly met with by us.
There is, nevertheless, no doubt but that it is genetically related to that just described.
The analysis is strikingly similar.
* Loc. cit., p. 129. f Loc. cit., p. 180.
222 PETROLOGY OF ROCK COLLECTIONS
Analysis of Augite-Biotite-Kersantite by Dr. G. T. Prior
SHO, 4 : ; : ~ 50=7al
1H ‘ : . 5 : : 2-71
INO ¢ : é : : ‘ . 17-08
Fe,0O; . ‘ : : : ; P 1-38
FeO. : ; 5 c C : 8-71
MnO . , : ; ‘ : ; 0-09
OOS P j : F : : 5-75
MeOme: : : ; 3 2 ; 3°63
a é : ; : : ; ‘ oes
Kes : : ; : ‘ ; F 6
IPO ? 5 j : 2 : 0-57
H,O-. F . : : ‘ , :
(HO, - : : , : : trace
99-99
Dr. Prior describes, from various occurrences in the Ferrar Glacier region, lampro-
phyric rocks related to banakite. These contain basaltic hornblende both porphyritic
and amongst the finer material of the base, but are specially distinguished as containing
porphyritic orthoclases. The field occurrences and the consanguinity, as indicated by
the analysis, suggest that these banakites are also a further variation of the one series.
Analysis (by Dr. Prior) of Lamprophyric Dyke related to Banakite from
the Ferrar Glacier Area
SiO, . : ‘ ‘ , ‘ . 48-22
TiO lw : ‘ ‘ f ; ; 2-09
RTOs": Pi Ue 4 eee) Ee eo ky
Fe,0, . : : j : : é 5-28
FeO. ‘ : ‘ : : i 3-90
MnO . ; x é F ; ‘ 0-10
CaO : : F < , 5 6:02
MgO . ; 3 . : : : 2-07
Na,O . 3 P 3 3 z : 4-94
KOR i : 3 5 3 4 3°47
IDOE ¢ c 3 6 : A ‘ 0:88
H,O+ . : ; ‘ ‘ ; : 2:89
H,O-. ; : P : ; ? 0-44
CO, and loss . ‘ F : , : 1:23
100-00
A lamprophyric dyke met with at Cape Ross was observed to be shot through with
abundance of idiomorphic hornblende needles. Unfortunately the specimens of this
rock were left at the Depot Island cache.*
Amongst Priestley’s collection from the Dry Valley moraines is a nice example of
a vein of this lamprophyre intersecting a pinkish granite-porphyry. Both of these
rock types correspond with those at Cape Irizar. The lamprophyre contains pheno-
erysts of porphyritic andesine, often zoned, and abundance of idiomorphic twinned
basaltic hornblende rods. Kaolinisation has attacked the interior of the felspars but
there generally remains a clear border zone. The fine material of the base consists of
tiny particles of plagioclase, orthoclase, quartz, and iron ores.
* See description by L. A. Cotton in appended Notes.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 223
Basic (Lampropuyric ?) INcLUSIONS
The granites ot South Victoria Land offer plentiful examples of basic inclu-
sions.
The inclusions fall into two classes. The one is biotitic, the other hornblendic.
The former, though of common occurrence, is unimportant and can be quickly
despatched. These are dark-coloured patches appearing at intervals in the face of
the granite. They are generally of but a few inches in diameter. The constituents are
the same as those of the granite, but the more basic minerals predominate.
A slide of one of these patches from the Cape Irizar granite exhibits the following
characters : Even fine-grained, lacking the porphyritic orthoclases of the parent granite.
Its relations to the enclosing granite indicate it to be endogenous, and an early
crystallisation product. It is allotriomorphic granular; grain size averages 1 mm.
Orthoclase is present in small amount. Oligoclase and andesine predominate. Quartz
is plentiful. Biotiteis abundant. Apatite and zircon are both much more concentrated
than in the granite. A few grains of sphene are also noted. This inclusion is, there-
fore, syenitic in character.
Much more important are the hornblendic (dioritic) masses distributed through
the grey gneissic granite of Depot Island. These are sub-angular to rounded and vary
from a few inches to several feet in diameter. They weather out in relief on the cliff
faces and have undoubtedly solidified prior to their inclusion in the granite. Their
chemical composition indicates that they are related to the granite magma itself, and
it appears as if they are earlier lamprophyric separations, subsequently burst through
by the mother magma.
These boulders are fairly uniform in texture, though frequently intersected by
coarser veins of the same constituents. The arrangement of these veins is pegmatitic
and the distribution of the minerals in the veins is uneven. Many of the veins pass
out of the inclusions into the gneiss, and show their period of formation to have
followed upon the solidification of the enclosing gneiss. The constituent * mimerals are
biotite, hornblende, plagioclase, quartz, and accessories, The latter include abundance
of a reddish-brown sphene.
Unfortunately our specimens were unrecoveredf from the depot and microscopic and
chemical analysis cannot be effected. There seems to be no doubt, however, but that
this is one of a dioritic class well represented in our collections. Examples of the
latter occur as erratics weighing as much as one hundredweight on Ross Island; they
are also found in the Ferrar Glacier collections, as erratics at Cape Irizar, and in the
vicinity of Mount Larsen.
Ferrar describes masses of hornblendic rock occurring in the pink granite of the
Kukri Hills as metamorphosed inclusions of the intruded dolerites. If this is so it
seems likely that there exists no relation between these inclusions and those of Depot
Island, for the analysis of the supposedly similar hornblendic rocks to be described
later in no way corresponds with that of a dolerite.
Further, Ferrar has noted the pink granite of the Cathedral Rocks || gradually
passing over to a coarse-grained diorite similar in most respects to the Depot Island
inclusions.
This evidence favours the origin of the basic boulders in the Depot Island gneiss
as earlier solidified differentiation products from the granite magma itself
* From field notes.
+ Since writing this the specimens have been recovered by the Scott Expedition of 1912. For
description see Paper following by L. A. Cotton.—D.M., 1916.
t Loc. cit., pp. 86 and 128. || Loe. cit., 36.
224 PETROLOGY OF ROCK COLLECTIONS
A comparison of the analyses of the granites and lamprophyre is worthy of note;
these are tabulated below:
Porphyry Dyke Kersantite Dyke
connected with grey | crossing red granite
granite—Mt. Larsen —Cape Irizar
Red granite— Grey Granite—
Cape Irizar Mt. Larsen
71:87 69-85 73-55 54-27
0-25 0:36 0-21 1:33
15-16 15-35 13-70 19-23
0-62 0-40 0-24 0-73
2-10 3°88 2°36 8:29
0-04 0-06 0-05 —
0-29 0-52 0-26 3-74
0-84 2:94 0-92 6-41
3°88 3°13 3:59 3:05
4-72 2-87 4-46 2-49
0-35 0-24 0:36 0:77
0-15 0:03 0-08 0-18
0:09 0-01 0:04 0-05
trace 0-50 os a
100-36 100-14
THE DIORITES
As suggested under the last section, there is reason to believe some of these at least to
be genetically closely connected with the earlier granites—probably lamprophyric
differentiation products. As nothing is yet known of the occurrences, im situ, of the
specimens hereunder described this point cannot now be cleared up. The rocks are of
such special interest that detailed descriptions are warranted.
SPHENE-BrioTITE-HORNBLENDE DIoRITE; NEAR Mount LARSEN
This was found as an erratic boulder from a moraine on the ice-fringe about 20 miles
south-east of Mount Larsen (Fig. 5, Plate IV). In the hand-specimen this rock is
even-grained and speckled-grey in colour. The obvious minerals are plagioclase,
hornblende, mica, and beeswax-yellow sphene.
Microscopic Characters. Hypidiomorphic-granular with grain size, in the section,
averaging 0°7 mm. (Fig. 1, Plate IV). A considerable amount of granular quartz is
present, often exhibiting shadowy extinction; it is certainly one of the latest crystal-
lised products. It is doubtful if any orthoclase is present, none could be recognised
n the two slides.
Plagioclase is present in abundance, ranging from acid labradorite to basic oligoclase.
The more basic individuals are early idiomorphic crystallisations. Zoning is almost
universal. Biotite is abundant; pleochroism—light yellow, bronze, to deep yellowish-
brown. Hornblende is plentiful; extinction angle about 13 degrees; pleochroism,
hight yellow, yellowish-green, to dark green. The hornblende encloses biotite. Sphene,
hight yellow by transmitted light, dull grey by reflected light; grains often 2 mm. in
length ; in some sections two sets of cleavage are clearly shown; crystallisation of the
sphene appears to have taken place after much of the felspar. Magnetite, apparently
titaniferous, appears in small not abundant grains usually embedded in the biotite.
Pyrites in scattered grains is more frequent than the magnetite. Apatite in very small
laths is rather abundant, usually embedded in the felspars. Occasional small grey
rods of zircon highly refracting and with straight extinction.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 225
An analysis made by A. B. Walkom, B.Sc., gave the following :
sid, . ‘ : . 561-91
TiO ee ‘: ‘ : 2-34
Al,0, ; j : » - 20°75 COMPOSITION OF THE NORM
Fe,0; . : . : 1-08 Quartz . : : : 2-88
iHeOe : 5 : 7-32 Orthoclase . : 5 14-46
MgO. - + + 8:05 Mibitess 6¥s 6% 4695-68
CaO ect 5 se OT Anorthite .. . . 31-41
Na,O . : . : 3-04 Corundum . ; t 1-63
CORE ec Moreen |p oee Hypersthene. . . 16-18
HL0+ . : : : 0-58 Ilmenite 3 : Fi 4-41
H,O-. : : : 0-04 Magnetite . : . 1-62
COs : : : 0-11 Apatite . Z ‘ : 1:34
Opp) geen aecn. 1 O58 ae
99°61
100-25
Chemico-mineralogical Classification: Class 2, Order 5. Rang 4, Sub-rang 3 (Hessose).
Specimens of a rock similar in all respects but containing less sphene were found
in the same moraine.
BiotitE-HORNBLENDE DiorITE; NEAR Mount LARSEN
A very similar rock to the preceding, though deficient in sphene. It was collected
from the lateral moraine near Camp Lake at the foot of the Larsen Glacier. This is a
fine granular grey rock exhibiting, to the naked eye, plagioclase, hornblende, and
biotite.
Microscopic Characters. Hypidiomorphic granular; average grain size in the
section 0-75 mm. The constituent minerals are quartz, plagioclase (andesine and
oligoclase), hornblende, biotite, apatite, magnetite, and sphene.
Quartz is present as irregular grains in small quantity only ; it is the last crystal-
lisation product; strain shadows are frequent. The plagioclase is zoned and ranges
between andesine and oligoclase; saussuritisation is advanced. The hornblende is
fresh and in idiomorphic or panidiomorphic forms ; twinning is frequent ; pleochroism
is strong (light yellow, deep greenish-yellow, and bluish-green. Bvotite is distributed
unequally, but always subordinate to hornblende ; the flakes are frequently bent ;
pleochroic (light yellow to deep yellowish-brown). Apatite isabundant as idiomorphic
prisms. Sphene is comparatively rare, occurring in minute grey grains.
An analysis of this rock made by A. B. Walkom, B.Sc., gave the following figures :
SOx s 9S se ies
HOW se oe salen 1 0-79
RUOte et eee tice ae 18-90 COMPOSITION OF THE NORM
Fe,0, . ° : c 2-03 Orthoclase . ; : 8-90
Hee ap ee ate ay F T8T Mibite ss ee A olde
Mg@Q . . «8:30 Anorthite . . . 30-30
CROs Mee fe aor 8 Sl Diopside) 2.) 4 | B39
NB OE a eye Sei3 Hypersthene. . . 9°31
OT aa ie ee wy TES Olivine Se ese (see
H,0 +. . 5 : 0-97 Magnetite . : - 3-02
me : : : : Poe Ilmenite 5 : : 1:52
Cie ce eeu
PO, «. ; Ae Apatite : : : ie
mages 98°69
107-90
226 PETROLOGY OF ROCK COLLECTIONS
Chemico-mineralogical Classification : Class 2, Order 5, Rang 4, Sub-rang 3 (Hessose).
BrotTitE-HORNBLENDE DtorItE; CAPE [RIzAR
An erratic specimen from Cape Irizar is similar to the first of the diorites described
above. In this, however, the grain size is somewhat larger and the constituents show
a greater tendency to panidiomorphism.
Microscopic Characters. The plagioclases show albite, carlsbad, and pericline twins
and are very strongly zoned ; the zoning, which is from andesine to oligoclase, is often
repeated a second time. Hornblende is more abundant than biotite and the prisms
reach 6 mm. in length. The biotite is often enclosed within the hornblende. Quartz
is more prominent than usual and often surrounding many crystals in poikilitic fashion.
Sphene appears in scattered grey grains ; in the hand-specimen these are yellowish-
brown. Apatite prisms are abundant. Zzrcon, occasional rods; one of these is
surrounded by a halo.
A rock of this class occurs amongst our collection from Dunlop Island, on the
coast-line farther to the south.
Amongst the collection from the Ferrar Glacier Moraines are two very striking
specimens of sphene-bearing amphibolites allied in composition to the preceding.
Sphene-bearing Amphibolite, Ferrar Glacier Moraines. This is a coarse-granular
speckled rock composed of dark amphibole, white plagioclase, quartz, flakes of biotite.
and grains of clove-brown sphene.
Microscopic Characters. Hypidiomorphic-granular texture. Quartz occurs in large
and small pieces. The plagioclase have the composition of andesine. Amphibole is
the most abundant constituent; it is uralitic. Sphene and apatite are unusually
abundant. Magnetite grains are rarer.
Another specimen of this class, though finer grained, comes from Dry Valley (Fig. 2,
Plate IV).
Under the subject of the lamprophyres of the granite following reference has been
made to the occurrence of a large outcrop of diorite in connection with the pink granite
at Cathedral Rocks, Ferrar Glacier, as described by Ferrar. The diorites described in
these pages are similar in composition, though differing somewhat in mineral contents.
The characters of these rocks are not typical of normal diorites but are suggestive of
lamprophyric separations. It is significant that their composition is very similar to
the kersantite dykes met with intersecting the granites; this is illustrated in the
following tabulated analyses :
I. Diorite from Camp Lake at the foot of the Larsen Glacier.
Analyst : A. B. Walkom, B.Sc.
II. Diorite from moraine about 20 miles south-east of Mount Larsen.
Analyst : A. B. Walkom, B.Sc.
III. Diorite from Cathedral Rocks, Ferrar Glacier.
Analyst : Dr. Prior.
IV. Kersantite crossing pink granite, Cape Irizar.
Analyst : A. B. Walkom, B.Sc.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 227
MnO — - _ —
MgO 3-30 3-05 3-78 3-74
CaO 8-81 7-07 8-25 8-41
Na,O 3-75 3-04 3-20 3-05
K.O : : ; 1-48 2-44 1-55 2-49
H,O + : A : : 0-97 0-58 0-94 0-77
H,O- F : : : 0-09 0-04 0-16 0-18
CO, : : : : 0-01 O-11 -- 0-05
P.O; j . ; , 0-57 0-52 0-38 =
Total . : : : 99-90 100-25 100-59 102-54
THE GABBROS
No occurrences were met with in situ. Erratic specimens, however, are not rare in
the McMurdo Sound region. These are often sphene-bearing, and in other ways
approach the sphene diorites so closely as to suggest a mutual relationship. A
specimen of this kind from the East Fork of the Ferrar Glacier, Upper Kukri Hills, is
an allotriomorphic-granular rock with average grain size about 3 mm. Plagioclase,
biotite, and uralite can be distinguished with the naked eye. The felspars, which are
basic-labradorites, are partly saussuritised ; they are twinned in broad lamelle after
the albite law, with occasional carlsbad combinations and frequent pericline twins.
Colourless idiomorphic diallage is present, but largely converted to uralite. The
uralite is colourless to greenish-yellow to bluish-green. Rarely small hypersthenes are
met. Occasional idiomorphic crystals of hornblende, dark greenish-yellow to light
yellow. Abundant biotite, ight yellow to red-brown. Accessories are apatite, magnetite,
and grey sphene.
Very similar to this, but more highly altered, is a sphene-bearing amphibolite from
the Dry Valley Moraines.
Hypersthene Gabbro. An erratic from Dry Valley. The constituents are: Basie
labradorite showing carlsbad, albite, and pericline twins ; some individuals are zoned ;
uralite after diallage, remnants of which only remain; hypersthene changing to
bastite ; biotite in scattered flakes ; magnetite in large original grains, and also as
secondary dust; apatite in medium-sized rods ; chlorite in connection with some of the
biotite.
Another specimen almost identical with this comes from the same locality.
Uralite Porphyry. A third specimen is more porphyritic and the plagioclases are
largely of a coarse lath-shaped variety. The hand-specimen is of a general dark grey
colour with scattered porphyritic black uralites. In many cases kernels of diallage
and hypersthene yet remain. Occasional flakes of biotite are present.
Bronzite Gabbro. This is a striking rock found in the lower moraines, McMurdo
Sound. Idiomorphic honey-yellow crystals of bronzite up to 6 mm. diameter are
studded through a white labradorite base.
II 2K
228 PETROLOGY OF ROCK COLLECTIONS
In the slide the bulk of the constituents is found to be composed of coarse lath-
shaped interlacing plagioclases ; the maximum symmetrical extinction angle on the
albite twins is about 35 degrees, it is therefore a labradorite. The bronzite is fresh.
There is present a very little apatite.
THE DOLERITES
The occurrence of extensive dolerite pipes and sheets intrusive in the Beacon Sand-
stone formation over a large area in the Ferrar Glacier region has been ably described by
H. T. Ferrar.* The latter, arguing from physiographic forms, further suggested the
extension of the area affected by these intrusions far to the northward and southward.
Our collections show the truth of this surmise even to a still wider extent. Fortunately,
as shown by Dr. Prior,} certain characters of this rock are quite distinctive, and serve
as reliable criteria in allocating erratic specimens to that particular intrusion. A
typical specimen of this dolerite is described by Dr. Prior as being of a mottled grey-
brown colour, medium-grained and showing no porphyritic crystals. Under the
microscope it is seen to be composed mainly of colourless augite—partly in long
prismatic crystals, and partly in irregular sub-ophitic plates—and plagioclase felspar
(labradorite chiefly) in stout prisms and lath-shaped crystals. Grains of magnetite and
ilmenite are very sparingly distributed.
The characteristic feature which serves as a criterion for distinction is the presence,
in the interstices of the rock, of more acid material showing quartz in micropegmatite
intergrowth with felspar.
This micropegmatite is sometimes abundant, in other cases it is almost absent.
The texture of these rocks varies in different outcrops, and is sometimes gabbroic.
In the same way slight alterations in the mineral constituents are to be noted, for
instance, in the amount of the residual micropegmatite ; at other times olivine makes
its appearance and the augite may be of the purplish titaniferous variety.
An analysis made and quoted by Dr. Prior of the dolerite from Knob Head, Ferrar
Glacier, is as follows :
SHOR ¢ : : : 3 : , 53-26
AKO), ; : ; : , ’ 0-70
INOS 6 : ; 5 : : : 15-64
Fe,0O; . : . é j ; ; 0-24
FeO. F 5 ; , ‘ : 7-44
MnO. : : F F 1 5 0-11
CaO : ‘ : - ‘ ; . 12-08
Na,O : ‘ ; : : 1-25
KcOn ; 2 5 , ; : 0-58
Bees 2 AOE fk) eee ea ee 04
EOpsks) WGN Nh Rea he, Beeb
H,O +. ; : ¢ é ; : 0-41
Total . ; ; é 4 : 92-10
Chemico-mineralogical Classification : Class 3, Order 5, Rang 4, Sub-rang 3 (Awvergnose).
Dolerite erratics of this class occur throughout the whole range of our collections.
Three specimens are represented in the Beardmore Glacier material. These are of
the normal type with the typical micropegmatite patches. The ferromagnesian mineral
is eee which is undergoing uralitisation, in some cases more advanced than in
others.
* Loc. cit., p. 49. + Loc. cit., p. 136.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 229
There are two specimens of the normal dolerite from one of the Ferrar Glacier
Moraines. From this locality, also, is a variation of the usual type which, however,
has already been noted by Dr. Prior: this is an olivine-bearing variety with violet
titaniferous pyroxene. Both the pyroxene and olivine are ophitic. Magnetite is
abundant and apatite unusually so. The structure is typical of the diabases but no
micropegmatite appears in the slide.
A dense variolite from the Stranded Moraines, McMurdo Sound, appear to belong
to the dolerite series, and may represent the quickly chilled marginal zone as
described by Dr. Prior.
At Dunlop Island, Cape Roberts, Cape Irizar, and the Moraines 20 miles south-east
of Mount Larsen other examples of the usual type met with as erratics.
At Cape Inizar, dolerite erratics are frequent and some diverge from the usual class
by containing a residual devitrified or variolitic glass and in some cases by uralitisation
of the pyroxene. One of these erratics from Cape Irizar, judged to be an example of
the dolerite formation which has suffered chemical metamorphism, is worthy of special
mention. The structure is coarse doleritic. It consists of well-zoned labradorite
felspars, a little interstitial quartz, deep-coloured biotite, and much uralitic hornblende,
observed, in some cases, to be after almost colourless pyroxene ; accessory minerals are
frequent apatite rods, and occasional grains of pyrites and magnetite. No micro-
pegmatite is observable.
DoLeRITE; Carpe BERNACCHI
A hybrid rock, an erratic from Cape Bernacchi, proves to be a variety of the
dolerite of unusual character. This is a dark grey fine-crystalline dolerite studded
with somewhat oval patches up to a half-inch in diameter of a pink-coloured coarser
crystallisation. These pink patches are arranged with their longer axes roughly
parallel, and are suggestive of the amygdules common in lavas.
Microscopie Characters. Most of the pyroxene of the grey dolerite has changed to
uralite and chlorite. The plagioclase is much clouded. Tron ores are abundant in
grains, partly leucoxenised.
The pink areas are more coarsely crystalline and differ in constitution from the
main body of the rock as follows: The felspars are orthoclase much kaolinised and
stained with hematite. Yellow biotite in small flakes is plentiful. Occasional small
idiomorphic hornblendes appear of yellowish and greenish tints. Jlmenite partly
leucoxenised in grains. Frequent patches of calcite occupying irregular spaces between
the orthoclases. The calcite is generally concentrated towards the centres of the
patches, and is always so arranged as to indicate its being the latest constituent.
The pink patches are regularly distributed. The plagioclases of the surrounding
dolerite are arranged with their long axes parallel to the boundaries of the patches.
The crystal arrangements in the patches sometimes show a marked radial development.
Occasionally the peripheral zone of the patches is rich in biotite. These facts indicate
that the pink patches are later solidifications than the main bulk of the rock and are
really of the nature of pegmatites occupying what apparently were residual spaces.
The association of this orthoclastic separation with the dolerite recalls the relation
of the residual micropegmatite to the normal dolerite.
A like case is that cited by Dr. Prior * of a dolerite erratic from Granite Harbour.
These facts lead to the suggestion of magma-splitting on a larger scale, whereby a
magma of the type producing the pink granite might be expected to result from the
splitting of the parent, more basic magma, in which the dolerites were concerned,
= Thayo, irr, S%8)
230 PETROLOGY OF ROCK COLLECTIONS
RECENT VOLCANIC SERIES
Rocks of this class are all erratics and were collected from moraines at or near the
present sea-level. They have obviously been transported by floating ice from the
volcanoes of McMurdo Sound.
As all the types have been met with 7m situ, and described either by Dr. Prior or
Dr. Jensen, a descriptive list is all that is required here.
Cape Roberts : Kenyte : Olivine basalt.
Dunlop Island : Kenyte : Basalts : Phonolite.
Cape Bernacchi : Kenyte : Olivine basalt.
Dry Valley.* Kenyte tuffs : Scoriaceous and tuffaceous lavas of the kenyte family :
Vesicular basalt : Tinguaite.
Stranded Moraines, McMurdo Sound : Kenyte with glassy base: Kenyte pitchstone :
Olivine-bearing kenyte : Glassy basalt with phenocrysts of olivine and augite : Vesi-
cular basalt: Vesicular basalt with porphyritic augites: Basalt containing much
hypersthene : Vesicular basalt containing porphyritic augite and olivine ; the vesicules
are largely filled with radial-fibrous calcite : Fine-grained tuff.
THE METAMORPHIC ROCKS
Metamorphic processes are evidenced on a grand scale in the basement complex of
South Victoria Land: amongst the types represented, obvious meta-sediments are
prominent ; these are marbles, mica-schists and injection-gneisses. Meta-igneous
rocks are represented by gneisses and amphibolites. In the case of the newer forma-
tions, local metamorphism near contacts is all that is evidenced. The vastness of the
subject does not allow of any adequate discussion based on the meagre collection at
hand ; but short reference to more interesting rocks only is warranted.
METAMORPHISM OF THE GRANITES
The majority of the gneiss exposures have all the appearance of having originated
by the dynamo-metamorphism of granite. Many of the granites have been noted to
show cataclastic structure and some of the outcrops may be seen passing into gneissic
varieties. Coarse granite-gneiss of this kind forms the promontory of Cape Roberts
whilst the granite mass of Granite Harbour, close by, shows clearly the first stages of
dynamometamorphism : this gneiss contains frequent basic schliers and both these
and the gneiss itself closely resemble those of the South Neptune Islands, off the South
Australian Coast.
An erratic block of granite at Cape Irizar, weighing several tons, shows well the
early stages of gneissification. This granite is of the Shap Fell type, carrying large
rectangular white anorthoclases. Both the mica and the large felspar exhibit a general
parallelism. The quartzes have been reduced to a mosaic: the felspars usually show
crush only round the edges. It contains, besides the usual constituents, a little grey
sphene, pleochroic yellow-brown allanite, and small apatite prisms.
A Gneissic Granite from a rocky point about eight miles South of Cape Irizar repre-
sents a more advanced stage. It is crossed by a narrow epidote vein. The quartzes
and felspars are completely crushed to form nests of granules strung out in a linear
direction. Accessory minerals are abundant, amongst them are several grains of
faintly coloured fluor spar.
* 'T. G. Taylor, of the recent Scott Expedition, discovered a local voleanie centre at Dry Valley
from which some of these may have originated.
FROM THE MAINLAND OF SOUTH VICTORIA LAND 231
Epidotised Granite from the same locality. This has suffered crushing and shows
bundant greenish-grey epidote along the crush-lines. The ferromagnesian con-
stituents are partly chloritised.
Another example of a crushed granite is an even-grained light-coloured gneiss from
the moraine twenty miles south-east of Mount Larsen.
This is a schistose granular rock consisting of quartz, orthoclase, plagioclase, a little
hght-coloured yellow and green biotite, and grains of ilmenite. Granulation is far
advanced.
Another specimen from the same moraine resembles this in every respect but that
it appears to represent a more advanced condition of dynamometamorphism. Granu-
lation is complete. Accessory minerals are abundant, including poikiloblastic pink
garnet, light yellow zircon, and rare apatite and titaniferous magnetite.
An Erratic Specimen from Marble Point, five miles North of Cape Bernacchi, is a
granite metamorphised by solutions which have passed along a vein now occupied by
reef quartz. The ferromagnesian minerals have been leached out in proximity to the
vein and the felspars completely saussuritised. Grains of leucoxene are abundant. The
quartz shows shadowy extinction. Away from the vein biotite appears, this is pleo-
chroic, colourless to orange-brown. The vein contains quartz with some pyrites.
Several gneissic specimens from the Beardmore Glacier are either meta-granites
or meta-arkoses of the composition of granite. Obviously it is impossible to distinguish
between these in the case of loose specimens.
METAMORPHISM OF THE BASIC IGNEOUS ROCKS
No cases of this kind were met with im setu, unless the case of the basic inclusions
in the granite of Depot Island is regarded as such. Ferrar refers to a metamorphism
of the dolerites by intrusion of the pink granites. It may be that some of the amphi-
bolite erratics referred to elsewhere in the text have originated in this manner. Among
these amphibolites there is a general development of uralite and saussuritisation of the
felspars.
Other metamorphic rocks of igneous origin are : A banded gneiss and a mica schist
with large poikiloblastic felspars, both from Dry Valley; also a sphene-bearing
actinolite gneiss from the upper glacial moraine, Ferrar Glacier.
METAMORPHOSED SEDIMENTS
Ferrar has described an extensive calcareous sedimentary belt outcropping in a
nearly north and south direction along the foothills of the Admiralty Range and towards
Cape Bernacchi. This we found to continue almost to Dunlop Island. At Cape
Bernacchi is a thick series of contorted and brecciated sedimentary rocks, prominent
amongst which is a saccharoidal marble. Zones of pseudo pebbles are evidence of
dynamic forces having been involved. Mineral solutions have risen in fissures inter-
secting the outcrops in all directions, and have effected powerful changes in the adjacent
strata.
Amongst these are quartz veins with occasional pyrites and quartz-felspar-muscovite
veins with abundant black tourmaline. The coarse saccharoidal marble is the rock
of chief interest. It contains a small percentage of graphite particles and crystals of
iron pyrites. Several crystals of copper pyrites were also noted. Where slight im-
purities occur, bands containing much epidote are met. A reddish biotite is also
frequently developed. Other patches contain red garnet.
At Marble Point, five miles to the north of Cape Bernacchi, a similar outcrop of
marble occurs. Associated with this is a fine mica-granulite, also pyrite- and epidote-
232 PETROLOGY OF ROCK COLLECTIONS
bearing quartz veins and irregular patches a few feet in diameter of coarse biotite-
bronzite rock.
Several fragments of the marble formation appear amongst the rocks collected from
the stranded moraines (Fig. 3, Plate IV). These are coarse-grained and granular ;
average grain size in the slide 0-8 mm. The rock consists almost wholly of calcite except
in dark bands, where graphite makes its appearance. Besides graphite there are minute
quantities of quartz, apatite, iron pyrites, and copper pyrites.
The red-brown biotite met with in the marble series is also a notable constituent
of several schists and gneisses from the Dry Valley Moraines. These have the appear-
ance of originating from calcareous slates and sandstones. The red-brown mica of one
of these specimens, apparently an altered sandstone, was found to contain a notable
percentage of manganese, to which, apparently, is due its colour. In another of these
rocks is a band rich in poikiloblastic garnets.
Other fine-grained mica schists originating from sediments are numerous. These
are similar to those frequently met with in the metamorphic zone bordering upon
granitic intrusive masses. In one case, from Dry Valley, the specimen shows an actual
contact of granite and mica schist, the latter representing an original sandstone.
In this case the granite is an even-grained grey variety. The schist is chiefly com-
posed of quartz showing undulose extinction. Strongly pleochroic yellow biotite is
abundant. There is present a very small amount of orthoclase showing Carlsbad
twins. Minute colourless garnets are frequent.
One of the specimens from the Stranded Moraines, McMurdo Sound, is apparently
an altered greywacke. It is of a general dark grey colour and composed of very regular
lamin about 1-5 mm. apart. It consists of mineral grains, chiefly quartz and felspar
in the lighter bands and admixtures of ferromagnesian minerals elsewhere. Small
particles of pyrites are distributed through the section.
From the Beardmore Glacier come several specimens of highly crushed granitic
rocks which, as already mentioned, there is reason to believe may be metamorphosed
arkoses. One of these from the Cloudmaker is of a light yellowish-grey colour showing
quartz, kaolinised felspar, and glistening scales of muscovite. Cataclastic structure is
evidenced under the microscope, and colourless garnets are frequent.
A very close-grained dark grey rock from the Upper Glacial Depot is very similar
to this in section. In this case granulation is complete. The quartz grains appear
as a mosaic under crossed nicols. The base is chiefly composed of alteration products
of the felspar, namely, epidote and sericite. Occasional grains of felspar still show albite
lamelle with extinction angles corresponding to acid oligoclase. Accessory minerals
are ilmenite, magnetite, apatite, and less frequent particles of sphene.
From the vicinity of the Cloudmaker comes a fine even-grained grey mica schist.
The chief constituents are quartz and biotite. It is intersected by irregular veins of
quartz and felspar.
In connection with the Beacon Sandstone reference has already been made to
quartzites developed therefrom by the intrusions of dolerite.
IXPLANATION OF THE PLATES
(Photographs by the Author)
PLATE I
Ficure 1.—A hand-specimen of Beacon Sandstone; x 3 diameter. Note the water-
worn quartzose pebble in the lower part of the photograph.
Ficure 2.—A concretionary nodule weathered out of the Beacon Sandstone, Ferrar
Glacier ; x 3 diameter. This has been fractured and hollowed out as described
in the text.
FicurE 3.—A saucer-shaped concretionary nodule weathered out of the Beacon
Sandstone, Ferrar Glacier ; x 2 diameter.
Ficure 4.—The pink granite, i situ, at Cape Inzar; x ? diameter. The large
crystals are pink orthoclase ; the finer material is a mixture of quartz, oligoclase,
hornblende, and orthoclase. A hornblende-biotite granite.
Figure 5.—The porphyritic grey granite from the Beardmore Glacier ; x 2 diameter.
The large individuals are chiefly anorthoclase ; the finer crystallisations include
quartz, orthoclase, microcline, biotite, and oligoclase. A biotite granite.
Ficure 6.—The grey granite, im situ, at the foot of the steep ascent to the Larsen
Glacier ; x 2diameter. This is an even-grained grey biotite granite.
Figure 7.—The even-grained grey granite from the Beardmore Glacier ; x # diameter.
The principal minerals are quartz, microcline, anorthoclase, oligoclase, biotite,
and muscovite.
PLATE II
Figure 1.—Orthoclase porphyry from the Stranded Moraines, East Fork, Ferrar
Glacier; x # diameter. The porphyritic crystals are orthoclase: the base
contains acid plagioclase, quartz, a little hornblende, and unresolvable devitrified
interstitial matter.
Figure 2.—Grey hornblendic orthoclase porphyry, in situ, at the Kukri Hills, Ferrar
Glacier; x ,°; diameter.
FicuRE 3.—Quartz porphyry, im situ, as a dyke-like mass cutting the grey granite
twenty miles south-east of Mount Larsen; x # diameter. Idiomorphic crystals
of quartz and orthoclase are seen distributed through a grey felsitic base.
Figure 4.—Black felspar porphyry occurring as an erratic at a rocky cape about
eight miles south of Cape Irizar; x 3 diameter. The lower light-coloured portion
of the photograph is a grey biotite granite which the porphyry has evidently
intruded.
PLATE III
Figure 1.—A microphotograph (x 17 diameters) of arkose from the Upper Glacial
Depot, Beardmore Glacier. The photograph shows dusty felspars and clear
quartzes ; less frequent are darker patches of mica.
Figure 2.—The same under crossed nicols (x 17 diameters). The albite lamelle
in some of the felspar grains are rendered apparent.
233
23 4. PETROLOGY OF ROCK COLLECTIONS
Figure 3.—A microphotograph, under crossed nicols (x 16 diameters) of the even-
grained light-grey granite from the Lower Glacial Depot, Beardmore Glacier.
The principal minerals present are quartz, anorthoclase, microcline, oligoclase,
biotite, and muscovite. Clear blebs of quartz are seen included in the felspar.
FigurE 4.—A microphotograph (x 16 diameters) of the pink granite from Cape Irizar.
The minerals present in the photograph are clear quartz, dusty anorthoclase, a
small amount of plagioclase, biotite, and hornblende. Biotite-hornblende granite.
Figure 5.—The same under crossed nicols (x 16 diameters). The anorthoclase and
plagioclase can now be distinguished by the twin lamelle.
Ficure 6.—A microphotograph (x 16 diameters) of the grey aplitic granite porphyry
from Cape Inizar. This particular slide illustrates the aplitic base which pre-
dominates over the porphyritic material. In the photograph, the dusty felspar
is readily distinguished from the clear quartz. The dark minerals are biotite and
hornblende.
FieurE 7.—A microphotograph (x 17 diameters) of a hornblendic aplitic granite
porphyry occurring as an erratic at Cape Irizar. The porphyritic light-coloured
individuals are zoned plagioclases. Idiomorphic hornblendes are abundant.
Figure 8.—A microphotograph (x 16 diameters) of a pink aplitic granite porphyry
occurring, in situ, amongst the granites at Cape Irizar. This comes from another
portion of the same outcrop as Fig. 6. The porphyritic individuals are plagioclase.
Figure 9.—A microphotograph, under crossed nicols (x 17 diameters) of a pink-
coloured graphic aplite occurring as an erratic at Cape Irizar. Note the graphic
quartz and orthoclase surrounding small porphyritic oligoclases.
PLATE IV
Fiaure 1.—A microphotograph (x 18 diameters) of sphene diorite from the moraine
twenty miles south-east of Mount Larsen. The minerals present visible in the
photograph are quartz, plagioclase, biotite, hornblende, sphene, and apatite. A
sphene-biotite-hornblende diorite.
KiaurRE 2.—A microphotograph (x 16 diameters) of a sphene-bearing amphibolite
collected as an erratic from the Dry Valley Moraines, McMurdo Sound. This
rock is an altered gabbro or basic diorite, and is notable for the amount of clove-
brown sphene which it contains. The larger dark areas in the photograph are
uralite ; smaller fragments of biotite are numerous. The felspar is of the com-
position of andesine and oligoclase. Grains of quartz are not infrequent. Sphene
and apatite are comparatively abundant.
FicurE 3.—A microphotograph under crossed nicols ( x 18 diameters) of a saccharoidal
marble found as an erratic at the Stranded Moraines, McMurdo Sound. Black
spots of graphite appear amongst the granular calcite.
Ficure 4.—A photograph of a hand-specimen of the pink granite from Cape Inizar
showing on the left-hand side of the photograph a junction with a black kersantite
vein; x 44 diameter.
Fraurg 5.—A photograph of a hand-specimen of the sphene diorite found as an erratic
at a moraine on the ice-fringe twenty miles south-east of Mount Larsen; x } dia-
meter. This rock is notable for the amount of beeswax-yellow sphene which it
contains. Fig. 1 is a microphotograph of the same rock.
PLATE I
lo
tos)
Ss)
Fic. 1 Fic.
Ere. 4 Fie. 5
Fic. 6 BGs 7
[To face p. 234
PLATE II
Fic. 4
Fic.
oo
PLATE III
Fie. 4 Fic. 5 Fic. 6
PLATE IV
Fic. 3 KirGs 1D
APPENDIX TO PART XIII
PETROGRAPHICAL NOTES ON SOME
ROCKS RETRIEVED FROM THE CACHE
AT DEPOT ISLAND, ANTARCTICA
LEO A. COTTON, B.A., B.Sc.
Dyke Rock From Cape Ross, SoutH or DEepot ISLAND
CRYSTALLINITY : holocrystalline.
Grain size: relative—porphyritic ; absolute—porphyritic crystals, 1 mm. ;
ground-mass, -1 mm.
Minerals present in decreasing order of abundance : hornblende, plagioclase, quartz,
magnetite.
Secondary mineral : kaolin.
The hornblende is the basic variety, deep brown in colour and strongly pleochroic.
The crystals are idiomorphic, excellent prismatic and basal sections being present. In
a number of basal sections a colourless kernel similar in shape and similarly situated
to the outline of the basal section was observed. ‘This kernel has a refractive index
and double refraction like that of felspar, but could not be with certainty determined.
There is a marked parallelism of the prismatic hornblende crystals.
The felspar is a plagioclase with very little decomposition. There is a tendency
to trachytic structure, but the parallelism of these crystals is not nearly so well marked
as in the case of the hornblende.
A few crystals of quartz were observed. These were rounded and possessed an outer
concentric shell. They are probably foreign to the magma and the shell represents
the result of chemical interaction. The shell consists of an undeterminable colourless
base resembling felspar, studded with minute crystals of basic hornblende radially
arranged.
The ground-mass of the rock consists of fine crystals of plagioclase and basic horn-
blende, with a few scattered crystals of magnetite. This rock may be termed a
Camptonite.
Dyke Rock From Cape Ross, SoutH or Deport IsLanp
Crystallinity : holocrystalline.
Grain size : relative—porphyritic ; absolute—phenocrysts, about 1 mm. (constituting
less than 5 per cent. of the rock) ; ground-mass, -05 mm.
Minerals present in their order of abundance : plagioclase, diopside, allanite (%),
quartz, magnetite.
Secondary mineral : chlorite.
II 235 2L
236 PETROGRAPHICAL NOTES ON ROCKS
The plagioclase is mostly contained in and makes up about half the ground-mass.
The crystals form an interlacing network between the meshes of which are contained
the diopside and allanite (?) grains. ‘The average size of the felspar laths is about -2 mm.
by -02 mm.
Diopside is very abundant in the ground-mass and most of the phenocrysts are of
this mineral. In the base the crystals take either a granular or tabular habit.
Allanite (?). This mineral is very abundant, and is quite comparable in quantity
with diopside. It is strongly pleochroic from light to dark brown. Prismatic sections
show a good cleavage parallel to the length. The refractive index and double refraction
are both high. The crystal grains are very small and uniform in size and average only
-02 mm. in diameter. On this account the sign could not be determined. The mineral
resembles, and probably is, allanite, but the small size of the grains makes the deter-
mination difficult.
Quartz is present only as a few inclusions. One large piece 2 mm. in diameter was
found quite rounded. A well-marked zone about -4 mm. in width surrounded the grain
and was evidently the result of the interaction of the magma and quartz. The zone
consists of small diopside crystals arranged with their lengths perpendicular to the
outlines of the grain.
Magnetite occurs as a few scattered grains in the ground-mass.
Chlorite occurs in feather-lhke aggregates but does not appear to be due to the
alteration of any of the primary minerals.
No flow structure is present. This rock may be termed an augite porphyrite.
GRANITE, SLIGHTLY FOLIATED, FROM Depot ISLAND
Crystallinity : holocrystalline.
Grain size : relative—even to coarse ; absolute—1 to 5 mm.
Fabric : granitoid, with very small patches showing micrographic intergrowth.
Minerals present in order of their abundance : orthoclase, quartz, albite, microcline,
biotite, labradorite, apatite.
Secondary minerals : chlorite and kaolin.
The orthoclase is fairly fresh, rather more than 50 per cent. being clear and un-
decomposed. It has a cloudy extinction and possesses a great number of small wavy
fracture lines. These indicate strain after consolidation.
The quartz for the most part has crystallised after the felspar, but small rounded
or oval patches occur as inclusions in the orthoclase. This with the small amount
of micrographic structure shows that some of the quartz crystallised before some of
the felspar. In this respect it resembles the Skiddaw granite.* On the whole the
bulk of the orthoclase crystallised before the bulk of the quartz.
These two minerals, quartz and orthoclase, constitute more than 85 per cent. of. the
rock. The remaining minerals occur rather sparingly. Only one crystal of labradorite
was observed. This was about 2 mm. in diameter and gave a symmetrical extinction
of 28° on the albite twin lamelle.
Very little apatite was found.
The rock is a granite having affinities with the pegmatite group.
* Q.J.GS. (1895), vol. li. p. 145.
FROM THE CACHE, DEPOT ISLAND, ANTARCTICA 237
Bastc ENCLOSURE IN GRANITE OF Depot ISLAND
Crystallinity : holocrystalline.
Grain size : relative—fine to medium : absolute—-5 to 1-5 mm.
Fabric : granitoid.
Minerals present in decreasing order of abundance ; labradorite, biotite, apatite,
sphene.
The labradorite is rather basic, having an extinction angle of 25° on the symmetrical
albite twins. This corresponds to a composition Ab, An,3.
The biotite is a deep brown variety, intensely pleochroic. There is a suggestion of
parallelism in the arrangement of the prismatic flakes.
A few small crystals of apatite are present.
No sphene was observed in either of the two slides examined, but some large por-
phyritic crystals, 6mm. x 4mm. were observed in the hand-specimen.
The rock is an uncommon type, being a pure mica diorite with sphene.
INDEX
ABLATION, i. 14, 19, 32, 33, 34, 35, 37, 44, 147, 193, 196,
199
Blue Lake, i. 33, 34, 161
C. Royds, i. 33, 34, 197
Clear Lake, i. 33, 34, 35
Coast Lake, i. 33, 34, 162, 165
definition of, i. 32, 44
Dry Valley, i. 95
Ferrar Glacier, i. 89, 92
Green Lake, i. 33, 34, 151
method of measuring, i. 33, 35
Pony Lake, i. 33, 166
Ross Barrier, i. 139, 142, 143, 145
Island, i. 139
Sunk Lake, i. 167
Terrace Lake, i. 168
Ablation-rippled surface, C. Barne, i. 166
Clear Lake, i. 156
Coast Lake, i. 162
Abrasion shelf, i. 9
Actinolite, ii. 183, 184
gneiss, i. 233, 234; ii. 183
schist, C. Royds, i. 111, 234; ii. 184
Adams, J. B., Lieut., i. 22, 30, 118
Adams Mountain, height of, i. 122
Adelie Land, i. 28, 29, 61, 202, 292, 293, 302, 318
sandstone and coaly shales, i 317
Adelie penguin guano, analysis of, i. 283
commercial value, i. 284
Admiralty Range, i. 24
Agirine, ii. 96, 102
Aigirine-augite, i. 257; ii. 96, 99, 101, 107, 108 119,
135, 136, 149
trachyte, Observation Hill, i. 257; ii. 101
African Sector, i. 1
Agglomerate, Turk’s Head, i. 226, 227
Aggradation, i. 146
plain, i. 9
Agricultural Department, Sydney, ii. 89
Alaska glaciers, i. 45
“ Alb” terrace, Beardmore Glacier, i. 120
Alb valley, i. 200, 288
Albite, i. 257; ii. 155
Alethopteris, i. 301
Alexander I Land, i. 318
Alge, i. 210, 273, 278
Backdoor Bay, i. 274
Blue Lake, i. 157, 160, 161
C. Barne, i. 229
C. Royds, i. 147, 149, 229
Clear Lake, i. 156, 157
Il 239
Algee—continued
Coast Lake, i. 33, 34, 157, 162, 164, 165
gas-producing, Green Lake, i. 153
Green Lake, i. 151, 157, 278, 279
Red Lake, i. 167
Round Lake, i. 165
Terrace Lake, i. 168
Algal peat, i. 44, 147, 262, 278, 279, 282, 283
analysis of, i. 280, 281
Coast Lake, i. 162, 164, 165, 279; ii. 15
near New Harbour, i. 283
Algonkian rocks between C. Bernacchi and Keettlitz
Glacier, i. 242
Alkali-pyroxene, i. 259
Alkaline rocks, i. 246, 307, 308, 309
differentiation in, ii. 93
Allanite, i. 64, 233, 245; ii. 211, 213, 217, 218, 235
Alpine glaciers, i. 45, 77, 140, 142, 173
valleys, i. 8
Alps, i. 317
Amazon, i. 292
American Sector, i. 1, 2, 3, 14, 290, 297, 298, 299, 301,
314
Ammonites, i. 313
Amphibolite, Marble Point, i. 233
sphene-bearing, Depot Island, i. 246
Amphipods, Dry Valley, i. 95
Amundsen, Roald, i. 2, 3, 4, 6, 11, 14, 19, 20, 22, 23,
29, 30, 31, 125, 127, 129, 138, 142, 143, 171, 188, 189,
298, 300, 301, 309, 318
Analcite, i. 257; ii. 94, 97, 99, 104, 114, 141
Analyses, chemical, of Antarctic Rocks :
Arkose, Beardmore Glacier, ii. 207
Banakite, Cathedral Rocks, ii. 222
Basalt, hornblende, Sulphur Cones, ii. 114
kulaitic, C. Bird, ii. 120
limburgitic, Hut Point, ii. 114
olivine, C. Barne, i. 114
Diorite, Cathedral Rocks, ii. 227
biotite hornblende, Mt. Larsen erratic, ii. 225
sphene biotite hornblende, Mt. Larsen erratic,
ii. 225
Dolerite, quartz-, aphanitic, C. Royds erratic, i.
157
Knob Head Mountain, ii. 157
porphyritic, C. Royds erratic, ii, 157
Granite, grey biotite, Mt. Larsen, ii. 213
pink hornblende biotite, C. Irizar, ii. 211
porphyry, aplitic, C. Irizar, ii. 216
Granulite, pyroxene, ©. Royds erratic, i. 161
scapolite bearing, C. Royds erratic, ii. 161
2M
240
Analyses, chemical, of Antarctic Rocks—continued
Kersantite, C. Irizar, ii. 221
augite-biotite, Ferrar Glacier, ii. 222
Kenyte, C. Royds, ii. 110
pumice, Mt. Erebus crater, ii. 98, 122
plagioclase, Turk’s Head, ii. 110, 122
The Skuary, ii. 110, 122
vitrophyric, The Skuary, ii. 110, 122
Limburgite, Mt. Erebus, ii. 114
Limestone, Cambrian, Beardmore Glacier, ii. 197
Tephrite, leucite, Crater Hill, ii. 114
Trachyte, hornblende, Observation Hill, ii. 98
phonolitic, C. Adare, ii. 98
Mt. Cis, ii. 98
Mt. Terror, ii. 98
phyro-hornblende, C. Bird, ii. 120, 122
Analyses of Antarctic Soils :
black soil, C. Royds, ii. 90, 91
dark soil, C. Royds, ii. 90, 91
gravelly black soil, C. Royds, ii. 90, 91
moraine silt, Dry Valley, ii. 90, 91
Analysis, chemical, of exanthalose, Deep Lake, i. 278
of felspar, Mt. Erebus, ii. 122
of mirabilite, Deep Lake, i. 277
of algal peat, Coast Lake, i. 280
of ash from peat, Coast Lake, i. 281
of penguin guano, C. Royds, i. 283
Anatina, i. 231, 273
Andalusite, ii. 185
Andean type of rocks, i. 299, 303, 308, 309, 314
Andersson, J. Gunnar, i. 285, 286, 297, 299, 301, 303,
311, 312, 314, 315, 316, 318
Andes, i. 3, 224, 246, 247, 296, 298, 299, 300, 303, 308,
316, 317, 319
volcanic cones, i. 224
West Antarctica, i. 317, 318, 319
Andrews, E. C., i. 9
Anorthoclase, i. 94, 195, 196, 218, 219, 227, 257, 258,
309; ii 94, 96, 100, 102, 103, 108, 135, 136, 137,
138, 142, 143, 144, 172, 178, 181, 213, 214, 215
Antarctandes, i. 3, 397
Antarctic Andes, i. 247, 298, 316, 317, 318, 319
correlation, i. 299
cyclone, i. 20, 25, 62
geological relations, i. 297, 320
glaciers, i. 46, 101, 132
movement of, i. 141
structure of, i. 132
horst, i. 3, 5, 6, 8, 14, 24, 25, 30, 31, 64, 77, 86, 99,
101, 114, 115, 116, 117, 138, 143, 199, 200,
208, 232, 241, 247, 252, 255, 290, 291, 292,
293, 294, 295, 298-302, 306, 307, 314, 316,
317, 318, 319
age of, i. 6, 201
economic minerals, i. 253
erosion of, i. 200
height of, i. 114, 115, 300
length of, i. 300
width of, i. 300
lavas, i. 260
paleontological evidence, i. 299
INDEX
Antarctic soils, ii. 89
volcanoes, i. 3
Antarctica, altitude, i. 1
area, i. 1
coast, i. 3
name given by Balch, i. 1
physiography, i. 3
sectors, i. l
shape, i. 1
summer temperature, i. 20
tectonic structure, i. 299, 316
Anthropornis Nordenskjoldi, i. 314
Anticline, Depot Island, i. 78
Anticyclone, i. 14
Antilles, Greater and Lesser, i. 297
Anvers Island, i. 285
Apatite, i. 233; ii 104, 107, 111, 135, 137, 188, 162,
166, 174, 176, 177, 184
Apatite allanite granite, i. 267
Apennines, i. 317
Aplite, i. 244, 246
C. Bernacchi, i. 85, 234
C. Roberts, i. 232
C. Ross, i. 80
C. Royds, i. 110, 111, 149
Drygalski Ice Barrier, i. 55
Green Lake, i. 150
Marble Point, i. 84, 233
Aplitic dykes, C. Irizar, i. 65
granite-porphyries, i. 244, 246
Aqueo-glacial, ii. 204
Araucaria, i. 313
Araucarites, i. 301
braziliensis, i. 313
cutchensis, 1. 313
Arber, Newell, Dr., i. 249
Archean rocks, i. 233, 310
Archeocyathine limestones, i. 5, 234, 235, 310, 312,
315
Archeocyathus, i. 236, 237, 240, 241, 242; ii. 82
ajax, i. 238
dissepimentalis, i. 237, 238, 240
ijizkit, i. 237, 240
profundus, i. 235, 237, 240
proskurjakowi, i. 240
retezona, i. 238, 240
spatiosus, i. 238
wirrialpensis, i. 237, 240
Arctic, i. 20
Ocean, i. 20, 22
Arctowski, H., i. 2, 3, 45, 285, 297, 299, 303
Arétes, i. 122
Arfvedsonite, ii. 96, 99, 120
Argentine Republic, i. 296, 313, 314
Arkose, Beardmore Glacier, i. 243, 245; ii. 206
felspathic, i. 251
Mt. Hope, i. 289
Upper Glacier Depot, i. 251
Armitage, A. B., Lieut., i. 123, 131, 253
Armytage, B., i. 88, 273
Arrival Bay, i. 203
INDEX
Atlantic type of rocks, i. 3, 299, 303, 304-11, 319
Atlas Mountains, i. 317
Atmospheric temperature, vertical distribution, i. 16
Auckland, i. 306
Augen-gneiss, C. Royds, i. 232
Cathedral Rocks, i. 232
Augite, i. 196, 257, 258, 259 ; ii. 100, 117, 124, 132, 137,
138, 154, 181, 183
magmatic resorption, ii. 141
phenocrysts, near Blue Lake, i. 112
titaniferous, ii. 138, 140, 142, 183, 229
Aurora, 8.Y., i. 302
Australasian Antarctic Expedition, i. 61, 317
Australia, main trend lines, i. 317
Australian alkaline province, i. 260
Sector, i. 1, 314
Auvergne Valley erosion, i. 291
Avalanches, Mt. Crummer, i. 199
Axel Heiberg Glacier, i. 131, 142
Backpoor Bay, i. 109, 148, 157, 208, 219, 222, 263, 273,
276
disruption of ice, i. 191
marine erosion, i. 207
raised beach, i. 114, 262, 269, 273, 275
sea-ice, i. 175, 182
terraces, i. 201, 207, 275
thickness of ice, i. 182
Backstairs Glacier, i. 60, 101, 187
Passage, i. 55, 56, 57, 231, 246, 271, 272, 275, 276
dimensions, i. 57
effect of thaw, i. 204
marine muds, i. 230, 231, 266, 267, 269, 270,
272, 273, 274
moraine, i. 242
serpule, i. 231, 266, 267
terraces, i. 287
Bage, R., i. 61, 202
Baie Marguerite, i. 317
Balanus, i. 271, 274
Balch, i. 1
Balleny Islands, i. 293, 301, 302, 305, 318, 319
Balloon Bight (now merged in Bay of Whales), i. 125,
126; 127, 137
observations by Capt. Scott Expedition, i. 123
Barkevikite, ii. 108, 124, 136, 180
Barne, M., Lieut., i. 125, 142
Barne Inlet, i. 117, 125, 136, 137
Glacier, width of, i. 140
Valley, i. 292
winds, i. 23, 24
Barrancas, i. 54, 62, 76
Barrier-ice, i. 163
Basalt, i. 196, 309
C. Barne, i. 219, 220, 259
C. Bird, i. 114, 218, 260
C. Royds, i. 223, 264
Clear Lake, i. 112
Crater Hill, i. 223
Dry Valley, i. 95
East Fork, Ferrar Glacier, i. 94
241
Basalt—continued
Inaccessible Island, i. 224, 225
Mt. Erebus, i. 111
near Solitary Rocks, i. 94
Stranded Moraines, i. 97
Sulphur Cones, i. 222
Tent Island, i. 225
Tertiary, Tasmania, i. 256
Tuff Cove, i. 221
Basalt beds, South America, i. 314
glass, Crater Hill, i. 222, 223
olivine, Harbour Heights, i. 83, 222, 225, 309
porphyritic, C. Royds, i. 111, 257
scoriaceous, Dunlop Island, i. 83
specific heat of, i. 18
variolitic, i. 195
Basalt-tuff, Graham Land, i. 314
Basanite, Auckland, i. 306
Hut Point, i. 259
Mt. Erebus, i. 257
Basic inclusions, ii. 223, 237
rocks, i. 77
Bay of Brialmont, i. 285
of Dalmann, i. 285
of Flanders, i. 285
of Whales, i. 11, 14, 20, 125, 127, 130, 131, 132, 137,
188, 300
current meter, i. 145
movement of ice, i. 129
sea-ice, i. 190
temperature of air, i. 189
winds, i. 189
Bay-ice, i. 137, 138, 140, 142, 145, 146
Backdoor Bay, i. 182, 190, 191
Beacon Sandstone, i. 5, 6, 8, 48, 55, 60, 64, 77, 195, 200,
241, 242, 243, 244, 245, 247, 249, 256,
260, 264, 265, 292, 300, 315; ii. 204
absence of glacial beds, i. 254
Adelie Land, i. 317
analysis of, i. 251
Beardmore Glacier, i. 120, 122
Buckley Island, i. 241, 248
C. Royds, i. 111
carbonaceous, ii. 206
chloritic, ii. 205
clayey, ii. 205
coal seams, i. 251, 252, 293, 300
colour of, i. 251
concretions, i. 251; ti. 205
correlated with Trias-Jura of Tasmania, i. 250
.David Glacier, i. 201
Dunlop Island, i. 241, 242
Ferrar Glacier, i. 247
Gondwana age, i. 250
Granite Harbour, i. 81
horizontal extent of, i. 252; ii. 147
igneous inclusions in, ii. 119
intruded by pink granites, i. 250
by quartz dolerite, i. 250
Mackay Glacier Valley, i. 201, 316
marbled, ii. 205
242
Beacon Sandstone—continued
Mt. Bartlett, i. 121
Buckley, i. 121
Cis, 1. 221, 257
Darwin, i. 241
Fridtjof Nansen, i. 300
near Horseshoe Bay, i. 114
petrological character, i. 251
Ross Island, i. 102, 308
saccharoidal, ii. 205
Solitary Rocks, i. 88
stalagmitic, ii. 205
Suess Nunatak, i. 298
Terracotta Mountain, i. 198
weathering of, i. 198, 199
“ Bearded ”’ structure, ii. 182
Beardmore Glacier, i. 3, 6, 8, 22, 30, 34, 82, 116-22,
130-33, 135, 137, 140, 141, 142, 201, 232,
234, 235, 241, 243, 245, 289, 299, 315
“alb” valleys, i. 200
crevasses, i. 37, 122
dimensions, i. 118
erratics, 1. 117
evidence of shrinkage, i. 122, 133, 134
former level of, i. 119, 122
thickness, i. 119, 120.
limestone, i. 242, 310
moraine, i. 120, 121, 235, 242, 264, 265
rate of movement, i. 141
sedimentary rocks, i. 150
“ trogtal ” valleys, i. 200
Valley, i. 117, 119, 120, 121, 234, 241, 291, 292
width of, i. 140
Beaufort Island, i. 5, 191, 228
Becke, i. 305
Beheaded glaciers, i. 45
Belgica Expedition, i. 303
Bellinghausen, i. 312
Belonites, ii. 107
Beluchistan Range, i. 317
Benson, W. N., i. 255, 256, 308; ii. 133, 142, 153
Berg, stranded, soundings near, i. 132
Bergen Railway, Norway, i. 32
Bergs, stranded, i. 12, 132
Bernacchi, L. C., i. 17, 84
Betic Cordillera, i. 317
Biloculina, i. 230
clay, i. 231; ii. 27
Bingley Glacier, i. 122
Biotite, i. 66, 78, 233, 245, 303; ii. 132, 137, 155, 157,
162, 170, 173, 174, 176, 177, 211, 212, 213
bleached, ii. 169
manganiferous, ii. 232
Bi-polar theory, ii. 27
Biscoe Islands, i. 317
Black Island, i. 5, 116, 271, 274, 287
moraines, i. 116, 274
Blacksand Beach, i. 12, 148, 185, 186, 197
icefoot, i. 177, 178, 190
Blizzard of February 15 to 18, 1908, i. 177, 207
February 19 to 21, 1908, i. 193
INDEX
Blizzard—continued
on Erebus, March 8 and 9, 1908, i. 212
Blizzards, i. 15, 17, 19, 23, 24, 28, 29, 30, 41, 42, 71, 74,
76, 95, 104, 105, 106, 131, 132, 148, 151, 177, 178,
180, 181, 182, 188, 189, 192, 197, 212
snow carried by, i. 101, 131
south-easterly, i. 12, 103, 180, 187, 189, 214
southerly, i. 12, 27, 62, 74, 76, 100, 187, 189
Blue bergs, i. 173
Blue Glacier, i. 98, 99, 121, 185
movement of, i. 141
Valley, i. 87
width of, i. 140
Lake, i. 88, 109, 148, 157, 165, 169, 201, 264; ii. 10
ablation, 1. 33, 34
dyke, i. 218
eskers, i. 112, 158, 159
moraine terraces, i. 112
narrows trench, i. 158, 161, 162
plan of, i. 158
prismatic ice, i. 151, 155, 156, 159, 160, 161,
162, 193
shafts, i. 36, 158; ii. 12
structure of ice, i. 159, 160, 161, 162; ii 11
summer thaw, i. 203, 204
temperature in trenches, i. 162
thickness of ice, i. 159, 161, 162
trenches, i. 159. 160, 161, 162
Valley, i. 154
Bolivian Andes, i. 298
Bombs, Mt. Erebus, i. 212
Bonney Glacier, i. 81
Valley, i. 81
Bony plates, i. 8
Borchgrevink, C. E., i. 123, 130, 260; ii. 118
Borchgrevink Inlet, i. 123, 127
Nunatak, i. 286
Borchgrevink’s Winter Quarters, i. 15
Boring of Ross Barrier, i. 144, 145
Bornemann, i. 237, 238, 241
Bostonite, i. 306
Boulder clay, i. 9, 194
C. Royds, i. 109, 110
Wilson Piedmont, i. 100
Brabant Island, i. 285
Brachiopods, i. 231, 266
Brachyphyllum mammillare, i. 313
Bransfield Strait, i. 317
voleanoes, i. 297
Brash-ice, i. 180, 191
Brazil, Gondwana coal-measures, i. 253, 298
Breccia, Lower Glacier Depot, i. 235, 241
Bridgman Island, i. 297, 301, 304, 318
Brine in ice-flowers, i. 181, 182
in sea-ice, i. 183
Green Lake, i. 152, 153, 154
Britannia Range, i. 23
British Antarctic Expedition, 1907-9, i. 229
1910-13, i. 8, 11, 13, 31, 63, 106, 130, 135,
136, 144, 145, 201, 223, 241, 298, 317
Museum, i. 248
INDEX
British National Antarctic Expedition, 1901-4, i. 106,
135 ; see also Discovery Expedition and National
Antarctic Expedition
Brittle-stars, i. 231
Brocklehurst, Sir P., i. 88, 162, 181
Bronzite, i. 255; ii. 143, 154, 156, 227
Brown, R. N. Rudmose, i. 230
Brown Island, i. 116
moraines, i. 116
Bruce, W. S., Dr., i. 1, 12, 230, 311, 312
Brucite, ii. 185
Bryum antarcticum, i. 229
argenteum, i. 229
Buchanan, J. Y., ii. 3
Buckley Island, i. 120, 241, 242, 248, 315
Nunatak, i. 248, 265
Bund structure in sea-ice, i. 42, 44
Burckhardt, C., i. 299
Burdwood Bank, i. 297, 312
Burrows, G. J., i. 251; ii. 148, 161, 168, 175, 207
Butchery “ Dog Depot,” i. 19
Butter Point, i. 89, 98, 99
Piedmont, i. 98, 99
width of fringe of glacier ice, i. 98
Bytownite, ii. 133
‘* By-washes,” i. 5
Catnozo1c, i. 8, 257, 291, 292
lavas and tufts, i. 208, 257
paleogeography, i. 285-96
Calcareous alge, ii. 81
Confervites primordialis, i. 241; ii. 81, 82
Epiphyton flabellatum, i. 241; ii. 81, 82, 83
fasciculatum, ii. 82, 83
Caleareous gastrule, i. 240
Calcite, i. 234; ii. 140, 141, 144, 173, 177, 179, 189, 191,
195, 196, 206
Cale-schist, C. Bernacchi, i. 234
Marble Point, i. 84, 233
Callaria, i. 274
Calottes, i. 45, 65
Cambrian age, climate, i. 236
crystalline rocks, C. Bernacchi, i. 85
Durness limestone, i. 111
limestone, i. 234, 242, 243, 298
Buckley Island, i. 248
limestones replaced by silica, i. 234
rocks, i. 235, 247, 315
Camera affected by cold, i. 81
Camp Lake, Mt. Crummer, i. 245
Campbell Glacier, i. 48, 135, 137
Islands, i. 302, 306, 319
Campbell’s, Lieut., party, i. 48
Camptonite, i. 308; i. 235
C. Adare, i. 3, 4, 5, 15, 17, 180, 189, 260, 299, 301,
310
Anna, i 285
Armitage, i. 222, 264, 287
Armytage, i. 13, 16, 102, 103, 125, 131, 184
Barne, i. 4. 6, 44, 108, 112, 132, 148, 186, 191, 196,
219, 259, 263, 277
243
C. Barne—continued
algze, i. 229
basalts, i. 259
glaciation, i. 106, 110, 263
height of, i. 108
ice-cliff, i. 108
lakes, i. 166, 167, 168, 169
lavas, i. 219, 220, 260
marine deposits, i. 210, 262, 263, 269, 270
erosion, i. 207
parasitic cones i. 218, 258
raised beach, i. 274, 275, 276
screes, i. 193
tarns, i. 151, 166
temperature of water in lakes, i. 169
weathering, i. 195, 196
Glacier, i. 13, 106, 107, 108, 191, 219, 227, 263
Pillar, 1. 219
Bernacchi, i. 84, 85, 86, 105, 233, 242, 247
Bird, i. 46, 112, 148, 213, 218
absence of foreign erratics, i. 114
description of, i. 114
distance from C. Royds, i. 114
extinct voleano, i. 217
fumarole, i. 218
magma reservoir, ii. 126
marine erosion, i. 207
rocks, i. 218, 260
soundings, i. 115
terraces, i. 201, 207, 275
to Erebus volcanic zone, i. 223
voleanic cone, i. 218
rocks, ii. 118
Bruce, i. 100
Crozier, i. 102, 125, 129, 133, 134, 136, 144, 145,
189, 208, 217
fault fracture, i. 223
glaciation, i. 102, 103, 146
Evans (see also The Skuary), i. 107, 227, 258
air temperature, i. 189
Fairweather, i. 299, 314
Goldie, i. 140
Horn, i. 302, 304, 317
Trizar, i. 48, 50, 64, 68, 101, 245, 287, 288
description of rocks, i. 64, 65, 66
dykes, i. 65, 66
erratics, i. 66, 233
granites, i. 64, 65, 66, 233, 245, 246, 308
height of, i. 65, 287
moraine, i. 265
Jones, i. 318
Kjellman, i. 301
Lyttleton, i. 140
North, i. 293, 300, 318
Philippi, i. 50, 54, 60
Roberts, i. 82, 232, 233
Ross, i. 78, 80
height of, i. 78
Royds, i. 8, 11, 12, 13, 15, 16, 17, 31, 32, 38, 44, 90.
94, 98, 102, 107, 110, 111, 112, 114, 117,
132, 133, 134, 148, 157, 166, 172, 182,
244
C. Royds—continued
188, 189, 193, 202, 203, 208, 213, 224,
227, 288
ablation, i. 33, 34, 89
alge, i. 147, 229
bay-ice, i. 190
blizzards, i. 41
chemical weathering, i. 198, 199
currents, i. 189
current indicator, i. 188
desiccation, i. 44
diatoms, i. 230
dimensions of, i. 111
distance from C. Bird, i. 114
erratics, i. 107, 108, 111, 112, 117, 149, 232,
234, 242, 246, 262, 263, 264, 287
evaporation, i. 34, 35
fracture, i. 208
glacial groove, i. 148, 194
valleys, i. 83
glaciation, i. 108, 109
ice-foot, i. 175-80
kenyte, i. 98, 112, 195, 196, 199, 263
lakes and tarns, i. 147, 148, 149, 153
lavas, i. 194, 223
lichens, i. 229
moraines, i. 262, 264
parasite cones, i. 218
precipitation, i. 34
pressure ridges, i. 185, 186
rocks, i. 110, 111, 224
rookery, i. 197
shafts, i. 38, 147
soils, ii. 89
saline accumulations, i. 198
soundings, i. 109, 115
strie, i. 194
temperatures, i. 192
thickness of ice, i. 109
tidal crack, i. 173
tides, i. 179
weathering, i. 195, 196
Washington, i. 4, 6, 46, 102, 144
marine erosion, i. 207
Westspring, i. 285
Captain Scott’s Depot A, i. 32, 143
Expeditions; see British Antarctic Expedi-
tions
Carboniferous, i. 256, 315
Cardot, Jules, i. 229
Carmen Land, i. 2, 4, 129, 131, 135, 188, 142, 145, 319
Carpolithes, Dunlop Island, i. 242
Caribbean Sea, tectonic lines, i. 297
Carpathian Mountains, i. 317
Castle Rock, i. 222
Cathedral Rock, i. 90, 91, 93, 232, 245
Caves in iceberg, i. 132
Central America, tectonic lines, i, 297, 317
Chalcedony, ii. 189
Challenger Reports, i. 193
Chalybite, ii. 190
INDEX
Chamberlain and Salisbury, Geology textbook, i. 32
Chapman, F., i. 230, 231, 234, 241, 266, 269, 271, 272,
274, 276, 312, 315
Reports on Ostracoda and Foraminifera, ii. 27, 37,
41, 49, 55, 81
Charcot, Jean, Dr., i. 1, 2, 45, 297, 303, 311
Charcot Bay, i. 69, 71, 100
Expedition, 1903-5, i. 246, 286, 303, 304, 317
Land, i. 301, 318
Chatham Islands, i. 302, 306
Cheetham Ice Tongue, i. 46, 64, 68
height, i. 68
Cheirolepsis gracilis, i. 313
Chemical weathering, C. Royds, i. 198
Cherty rocks, i. 111, 235
Chili, i. 295, 297, 300
Chiton, Professor, i. 231, 266
Chlorite, i. 251; ii. 154, 178, 179
Chromite, ii. 132, 133
Chondrodite, i. 234
Chonos Archipelago, i. 297
Christmas Camp, i. 195
Cirque erosion, i. 201, 293
glaciers, i. 82, 120
Cirques, i. 45, 46, 76, 122, 200, 201
Beardmore Glacier, i. 201
Lower Glacier Depot, i. 119
Mawson Glacier, i. 201
Mt. Chetwynd, i. 201
Reeves Piedmont, i. 201
structure of, i. 201
Cladophlebis, i. 301, 312, 313
denticulata-nebbensis-whitbyensis, i. 312
Clarke Barrier, i. 64, 65
Glacier, i. 265
Clay shale, Ferrar Valley, i. 247
with impression of rootlets, Drygalski Barrier,
1: 55
Clear Lake, i. 89, 148, 154, 158, 165, 201; 11. 15
ablation, i. 33, 34, 35
ablation-rippled surface, i. 156
black mud, i. 156, 157, 230
crystalline ice, i. 155
prismatic ice, i. 151, 155, 156
snow tabloids, i. 156
summer thaw, i. 203, 204
temperature in trenches, i. 156, 157
terraces, i. 155
thickness of ice in trenches, i. 155, 156
trenches, i. 155, 156, 157
trend of axis, i. 109
View Peak, i. 158
Cliff glaciers, i. 45, 93
Climate, semi-glacial, ii, 203
Clinochlore, ii. 185
Cloudmaker, i. 121, 122, 243
moraines, i. 120, 236, 289
Coal, age of, i. 250, 254, 255
analysis of, i. 249, 250
Buckley-Bartlett Nunatak, i. 253
in Beacon Sandstone, extent of, i. 252, 253, 254
INDEX
Coal—continued
Mt. Bartlett, i. 121
Buckley, i. 121
seams in Beacon Sandstone, i. 251, 252. 315
seven seams in Nunatak, Beardmore Glacier, i. 122,
248
thickness of, Beardmore Glacier Nunatak, i. 254
Santa Catarina basin, i. 253, 254
Coal-bearing rocks, Mt. Buckley, i. 121
near the Cloudmaker, i. 120
sandstone, i. 6, 316
relation to Tasmanian, i. 316
Coalfields, probable area of, i. 293
Coaly shales, Adelie Land (King George Land), i. 317
Coast Lake, i. 148, 162, 165, 201; ii. 14
ablation, i. 33, 34, 162
stake, i. 163, 165
alge, i. 157, 162, 164, 165, 279
algal peat, i. 162, 164, 165, 279
ice-cracks, i. 90, 163, 164, 165
plan of, i. 163
rippled ice-surface, i. 162
salinity, ii. 14
section of ice, i. 162, 164, 165, 279; ii. 14
of peat deposit, i. 279, 280
structure of ice, i. 162, 164, 183; ii. 15
summer thaw, i. 203, 204
temperature of water, i. 169
in trenches, i. 164, 165
thickness of ice, i. 162, 164, 165
trenches, i. 162, 164, 165, 279
platform, i. 9, 80, 121
Piedmont, i. 121
Coastal plain, Keettlitz Glacier to C. Washington, i. 4
Coat’s Land, i. 2, 319
Cockburn Island, i. 314
Cohen, Miss F., B.A., B.Sc., ii. 136, 149
Cold poles, i. 14, 31
Columnare, i. 312
Concentric weathering, i. 194
Concretions, Beacon Sandstone, i. 251
Confervites primordialis, i. 241
Coniferous wood, i. 256
Conifers, i. 313
Contraction cracks, C. Royds, i. 186, 187, 263
Green Lake, i. 150
Control specimens for measuring ice loss, Ross Barrier,
i. 139, 140, 145
Copper pyrites, C. Bernacchi, i. 233; ii. 232
Cora Island, i. 269, 276
Corals, i. 230, 266
Cordierite, ii. 144
Cordillera, North America, i. 303
Real, i. 298
Corner Glacier, i. 48, 135, 137
Corrie glaciers, i. 5, 45, 86, 119, 120
Corrosion hollows, i. 139, 190
Corundum, ii. 180, 181, 182
Coscinacyathide, i. 240
Cossyrite, ii. 96, 97, 99, 126, 134
Cotton, L. A., B.A., B.Sc., ii. 235
245
Cotton Glacier, i. 46, 64
Valley, i. 76
Coulman Island, i. 5
Craigie, K., i. 12, 77
Crater Hill, i. 222, 223, 259
height of, i. 264
Cretaceous, i. 5, 256, 291, 298, 299, 300, 301, 313, 316,
317
fauna, i. 311
Graham Land, i. 314
New Zealand, i. 314
Crevasses, Beardmore Glacier, i. 37, 122
C. Barne Glacier, i. 108
Ferrar Glacier, i. 89, 91, 93
Glacier Tongue, i. 103
Horseshoe Bay, i. 112
Mt. Nansen, i. 36
Nordenskjéld Ice Tongue, i. 76
Ross Barrier, i. 102, 127, 130, 132
Turk’s Head Glacier, i. 106
White Island, i. 125, 126
Cross-sections, Drygalski Ice Tongue, i. 141
ice-streams, western side of Ross Sea, i. 140
Crown Prince Gustaf Channel, i. 318
Crummer massif, i. 57, 82
Cryohydrates, i. 42, 183, 184; ii. 18
solidified, ii. 10, 16, 18
Cryohydric temperature, ii. 10
Crystalbrook, South Australia, i. 242
Crystallinity, Ross Barrier, i. 145
Crystals, eegirine, ii. 149
hexagonal, ii. 21
negative, ii. 13, 132
trigonal, ii. 19
Cumulus clouds, i. 187, 189, 190
Current indicator, C. Royds, i. 188
meter, Bay of Whales, i. 145
near C. Bird, i. 188, 189
observations, Ross Sea, i. 190
off Ross Island, i. 188
Weddell Sea, i. 189
Currents under Ross Barrier, King Edward VII Land,
i. 188
McMurdo Sound, i. 145
main face of Barrier, i. 145
Cwm erosion, i. 201
glaciers, i. 45
D Buiter, i. 90
D, Peak, i. 92
D, Peak, i. 92
D, Peak, i. 92
Daly, Professor R. A., ii. 93, 117
Danco Land, i. 2, 285, 290, 317
Danish Greenland, i, 45
Darwin, C., i. 299
David, Professor T. W. E., ii. 27, 55, 93, 117, 148, 168,
189, 210
David Glacier, i. 29, 46, 48, 50, 60, 61, 62, 66, 137, 201,
287, 288
area, i. 60
246
David Glacier—continued
Beacon Sandstone, i. 201
ice-falls, i. 201
Piedmont, i. 61
width of, i. 140
Davis, J. K., Capt., i. 11, 12, 52, 302; ii. 55
Davis Glacier, i. 46, 50, 64, 66, 68, 101
height of, i. 68
width of, i. 140
Day, i. 30, 127, 133, 135, 136
Debenham, F., i. 8, 95, 97, 141, 208, 223, 243, 250, 298,
316
Deception Island, i. 297, 304, 318
Deep Lake, i. 102, 148, 166, 167, 168, 201, 229
trend of axis, i. 109
De Geer, Professor, i. 267
Deinosaur remains, South America, i. 298
Dellbridge Islands, i. 208, 224, 289
Delphinornis Larsenii, i. 314
Dentalium, i. 231
Denudation, i. 199, 202
Depot A; see Scott’s Depot A
A of Discovery Expedition, movement of, i. 125,
127, 129
Island, i. 78, 80, 81, 244, 246, 288, 300, 308; ii.
203, 235
height of, i. 78, 288
Nunatak, i. 201
Descent Pass, i. 87, 90
height of, i. 87
De Schollzrt Canal, i. 285
Desiccation, C. Royds, i. 44
D’Urville Wall, i. 63
Deutsche Sudpolar Expedition, 1901-3, i. 305
Deutschland, i. 12
Devil’s Glacier, i. 11, 131, 132, 135, 142, 146, 314
Devonian, i. 5, 8, 243, 250, 298
fish, i. 8, 250
sandstone, i. 311
Diabase, C. Irizar, i. 50
Clear Lake, i. 112
intrusions, i. 256
Konga type, i. 255
Mt. Cis, i. 257
Mt. Hope, i. 119, 289
sills, i. 6, 64, 112, 255, 256, 315
Sweden, i. 308
Diabase-porphyry, C. Royds, i. 111
Diallage, ii. 227
Diatomaceous mud, i. 44, 262
ooze, i. 180
Diatoms, i. 11, 231; ii. 55
Backdoor Bay, i. 274
C. Royds, i. 230
Clear Lake, i. 156, 230
Louis Philippe Land, i. 230
Mt Erebus, i. 210
near Blue Lake, i. 157
Ross Sea, i. 230
Dicranella Hookeri, i. 229
Dictyocyathus, i. 238
INDEX
Differential erosion, i. 10, 137, 138
Diopside, ii. 120, 165, 166, 236
chrome, ii. 132
Diorite, Camp Lake, i. 245
Cathedral Rocks, i. 245
enclosures, Depot Island, i. 78, 244, 246
moraine, Mt. Larsen, i. 245
Diorities, i. 244, 245, 246, 264, 303, 304, 309
Discovery Expedition, 1901-4, i. 11, 35, 48, 115, 116,
123, 125, 127, 130, 133, 184, 224, 227, 253
Winter Quarters, i. 15, 16
Discovery Gulf, i. 234
Dog Depot, i. 30
Dogger Bank, i. 146
Dolerite, Antarctic, distribution of, ii. 153
comparison with that of British Guiana, ii. 160
of South Africa, ii. 159
of Tasmania, ii. 159
C. Bird, i. 114, 218, 260
C. Trizar, i. 66
C. Royds, i. 264
Drygalski Ice Barrier, i. 55
Ferrar Valley, i. 247
Mackay Glacier, i. 81
Mt. Howard, i. 67
Solitary Rocks, i. 88
South Victoria Land, i. 308
Tasmania, i. 256
quartz-, origin of, ii. 158
sills, i. 245, 256
Beacon Sandstone, i. 254
South Africa, i. 256
Dolomite, ii. 190, 192
Dolomitice breccia, Lower Glacier Depot, i. 235
limestone, Buckley Island, i. 242
Dolomitisation, ii. 189
Dominion Range, i. 121
Dongas, i. 54, 55, 62
Doumer Island, i. 286
Drake Strait, i. 302
Dreadnought, i. 130
Dredging-line, ice-crystals on, i. 112, 183
Drygalski, i. 32, 45, 50, 286
Barrier, i. 23, 24, 36, 48, 62, 63, 66, 68, 187
afloat, i. 62
aground, i. 62
height, i. 52
outlier of Great Ice Barrier, i. 63
Glacier, i. 12, 13, 26, 46, 50, 51, 52, 61, 100, 116,
135, 136, 187, 270
glacier-cut cliff, i. 50, 116
Ice Barrier, i. 173
“alb” valleys, i. 200
crevasses, i. 52, 53, 54
cross-section of, i. 141
effect of thaw, i. 204
erosion, i. 200, 207
ice, density of, i. 52
thickness of, i. 52, 63
barrancas and dongas, i. 54, 62
length of, i. 61
INDEX
Drygalski Ice Barrier—continued
maximum glaciation, i. 62, 63
moraine, i. 62, 63
movement of, i. 62, 141, 269
soundings, i. 52, 53, 54, 63
submarine esker, i. 62, 63
thickness of ice, i. 52, 141
tidal cracks, i. 52, 53, 54, 100, 117
Tongue, i. 9, 18, 22, 35, 46, 48, 50, 51, 52,
53, 54, 55, 61, 66, 74, 98, 99, 105,
106, 114, 117, 191, 293
dimensions, i. 48
Piedmont, i. 54-7, 62, 63, 98
length, i. 62
temperature, 1. 187
Drygalski-Larsen-Reeves Piedmont, i. 269, 270
Drygalski-Nansen Piedmont, i. 63
region, thaw effect, i. 204
Drygalski-Reeves Piedmont, i. 46, 56, 57, 135, 136, 137,
138, 145, 146
effect of thaw, i. 204, 205, 206
Barrier, structure of, i. 63
key to structure of Ross Barrier, i. 63, 138, 139
Dry Lake, i. 158
Valley, i. 6, 85, 86, 87, 92, 95, 96, 101, 115, 208,
217, 233, 273, 277
erratics, i. 233
fault fracture, i. 223
fossils, i. 87
lavas and tufts, i. 223
marine muds, i. 266
peat deposits, i. 278, 283
raised beach, i. 273, 275, 276
soil, ii. 89
Dun, W. S., i. 241, 313
Dundee Island, i. 312
Dunedin, i. 305, 306
Dune glaciers, i. 45
Glacier Tongue, i. 105
Dunite, ii. 132
Dunlop Island, i. 82, 83, 84, 87, 233, 241
height of, i. 288
D’Urville Wall, i. 287
Dust wells, i. 132, 172
Dyke rocks, i. 244, 245, 246, 298
Dykes, Backstairs Passage, 1. 246
Blue Lake, i. 159, 218
C. Trizar, i. 65, 66
C. Roberts, i. 232
C. Ross, i. 78
C. Royds, i. 218
Granite Harbour, i. 81
Penguin Rookery, i. 218
Dynamic Geology, i. 14
East Africa, i. 309, 310
Antarctica, i. 5
Fork, Ferrar Glacier, i. 101, 115, 288
Valley, i. 87, 94
Eastern Australia, i. 310, 319
Echinoderms, i. 230
247
Echinoid spines, Backdoor Bay, i. 266, 273, 274; ii. 55
Economic minerals, i. 253
Ecuador, i. 306
Ekman Bay, i. 269
Elatides, i. 313
Enclosures, i. 78, 219, 303
Enderby Land, i. 292
quadrant, i. 1
“ Endless belts” of air, i. 25
Englacial moraine, i. 19, 146, 173
Enstatite, i. 255; ii. 108, 115, 117, 132, 154, 156
Enstatite-augite, i. 255, 308 ; ii. 153, 154, 155, 156
Enstatite basalts and dolerites, C. Bird, i. 114
olivine basalt, i. 259
Eocene, i. 291, 314
Graham Land, i. 314
South America, i. 314
Eospheniscus Gunnari, i. 314
Epidote, i. 84, 233, 234, 267 ; ii. 106, 176, 178, 183, 218,
230, 231
Epidotised granite, Marble Point, i. 247
Epiphyton flabellatum, i. 241
Equisetacee, i. 312
Equisetum, 1. 312
Erebus and Terror Expedition, 1841-42, i. 133
Erebus lavas and tuffs, i. 257
series of eruptions, oldest, i. 112
volcanic series, disappearance of, i. 112
Erosion, i. 199, 200
cirque, i. 201
ewm, i. 201
differential, i. 10
glacial, i. 200, 201
ice, i. 199
marine, i. 98, 201, 207
Erratics, i. 107, 114, 262
Beardmore Glacier, i. 117
Black and White Island, i. 287
Blue Lake, i. 161
C. Armitage, i. 222, 287
Bernacchi, i. 84
Bird, i. 114
Trizar, i. 66, 233, 288
Roberts, i. 82
Royds, i. 107, 110, 111, 112, 149, 228, 226,
227, 232, 234, 242, 262, 263, 264, 287, 308
Clear Lake, i. 112
Crater Hill, i. 222, 223, 264
described by Dr. Woolnough, i. 260; il. 169
Dry Valley, i. 95, 233
granite, i. 98, 108, 111
Green Lake, i. 150
Hut Point, i. 223, 264
Mackay Glacier, i. 82
Marble Point, i. 247
Mt. Cis, i. 221
Mt. Hope, i. 119, 120, 242
near C. Ross, i. 79, 263
Horseshoe Bay, i. 114
Observation Hill, i. 222
Pony Lake, i. 111
248
Erratics—continued
Ross Barrier, i. 117
Island, i. 114, 263
schistose, i. 98
stranded moraines, i. 97
Tuff Cone, i. 221
Eruptive rocks, i. 244
Mt. Christensen, i. 318
Haddington, i. 318
Paulet Island, i. 318
South America, i. 297
Eskers, Blue Lake, i. 112, 158, 159
Mt. Cis, i. 220
Erebus, i. 221
submarine, i. 62, 63
Glacier Tongue, i. 106
The Skuary, i. 107, 228
Essexite, i. 255; ii. 153
Etheridge, R., i. 241
Ethmophyllum dentatum, i. 238
Europe, glaciation of, i. 145
Evans, E. R. G. R., Commander, i. 130, 136, 144
F. P., Capt., i. 11, 115, 132, 174
Evans Coves, i. 46, 48, 56
Evaporation, i. 198, 202
C. Royds, i. 35
Exanthalose, i. 277
Expedition Antarctique Belge, i. 45
Frangaise, i. 45
Fagus, i. 313
Falkland Islands, i. 8, 298, 302, 311, 312, 318
Fast-ice, i. 46, 180, 191
Fault fracture, C. Crozier to Dry Valley, i. 223
scarp of Mt. Nansen, i. 4
Faults, i. 5
cross, i. 6
downthrow, Ross Sea, i. 109, 221
east and west, i. 86, 223
north and south, near C. Adare, i. 5
parallel, i. 86
Victoria Land, i. 221
Felsites, pink, C. Ivizar, i. 50, 66
Felspar, anorthoclase porphyritic, Mt. Cis, i. 221
porphyries, i. 246, 263, 267, 308, 309
porphyry, C. Royds, i. 110, 264
sanidine, Mt. Cis, i. 221
Felspars, i. 65, 78, 107, 178, 179, 180, 196, 218, 219, 224,
225, 226, 2277, 233, 251, 254, 258,
259, 303, 304; see also under
Specific Titles
lime-soda, i. 246
summit Mt. Erebus, i. 212, 213, 215
analysis of, ii. 122
Ferrar, H. T., i. 5, 86, 87, 88, 92, 102, 103, 110, 116, 132,
141, 142, 210, 222, 223, 225, 227, 234, 241,
245, 246, 247, 248, 250, 253, 263, 264, 271,
274, 287, 300; ii. 209
classification, i. 45
Ferrar Glacier, i. 3, 8, 26, 28, 46, 63, 64, 77, 81, 82, 86-95,
98, 100, 101, 114, 115, 133, 162, 288, 289
INDEX
Ferrar Glacier—continued
crystalline ice, i. 88, 89
moraine, i. 233, 243
movement of, i. 141
prismatic ice, i. 155
shrinkage of, i. 133, 134
Valley, i. 6, 87, 90, 98, 105, 200, 203, 232, 233,
253, 287
Beacon Sandstone, i. 247
frost-weathering, i. 194, 195
hanging valleys, i. 201
magnesia salts, i. 199
serees, i. 195
width of, i. 88
wind-weathering, i. 197, 198, 199
width of, i. 140
Ferrite, ii. 102, 103
Fiji, i. 307
Filchner, Lieut., i. 2, 12, 122
Finger Mountain, i. 255
Fiords, i. 4
Fireclay, Mt. Bartlett, i. 121
Mt. Buckley, i. 121
Firnfield, i. 24, 45, 144
Fish, Dry Valley, i. 95
plates, Granite Harbour, i. 243, 250, 298, 315, 316
Flagstaff Point, C. Royds, i. 98, 175, 177, 182, 184, 185,
186, 191, 194, 218, 258, 263
marine erosion, i. 207
thickness of ice, i. 182
Floating ice, i. 46
Floe-ice, Granite Harbour, i. 180
McMurdo Sound, i. 180
‘* Flood-gauge,” glacial, Mt. Hope, i. 119
Fluorspar, i. 233; ii. 109
Fohn effect, i. 19, 20, 62
wind, i. 118
Fonck, i. 299
Foraminifera, i. 230, 231, 266, 269, 272, 273, 274; il.
Zip AN, ODS OT
bathymetrical distribution of, ii. 76
Anomalina ammonoides, ii. 70
polymorpha, ii. 70
Biloculina, i. 230; ii. 27
bradii, ii. 42, 57
depressa, Ui. 27, 57
elongata, ii. 28, 41, 57
wrreqularis, li. 42, 57
levis, ii. 27, 28
sarsi, ii. 27, 28
Bolivina textilarioides, ii. 65
Bulimina seminuda, ii. 27, 29, 41, 43
Cassidulina, ii. 27
oblongata, ii. 30, 41, 43, 65
parkeriana, ii. 27, 30, 41, 43, 65
subglobosa, ii. 27, 31, 41, 44, 65
Cornuspira foliacea, ii. 60
involvens, li. 29, 41, 43, 60
Cristellaria articulata, ii. 67
convergens, ii. 27, 32
crepidula, ii. 44, 67
Foraminifera—continued
Cristellaria gibba, 1. 44
Discorbina vesicularis, ii. 27, 33
vilardeboana, ii. 27, 33
Ehrenbergina pupa, ii. 27, 31
serrata, ii. 27, 31, 41, 44, 65
Globigerina ceequilateralis, ii. 69
bulloides, ii. 68, 75
dutertret, ii. 69
inflata, ii. 69, 75
triloba, i. 68
Haplophragmium canariense, ii. 63, 75
latidorsatum, ii. 64, 75
scitulum, i. 64
Hyperammina elongata, ii. 61
Largena apiculata, ii. 66, 75
globosa, ii. 66
marginata, ii. 66, 75
orbignyana, il. 66
schlichti, ii. 66
squamosa, i. 31
Marsipella cylindrica, ii. 62
elongata, ii. 61
Miliolina agglutinans, ii. 58
bicornis, ii. 58
circularis, ii. 42
oblonga, var. wrenacea, li. 59, 75
subrotunda, var. striata, ii. 58, 75
tricarinata, ii. 29, 59
vulgaris, i. 58
Nodosaria (glandulina), ii. 27
levigata, ii. 27, 31, 41, 44, 67
rotundata, ii. 27, 32, 41, 44, 67
(dentalina) communis, ii. 67
Nonionina depressula, ii. 70, 75
scapha, var. bradii, ii. 71, 75
stelligera, ii. 27, 34, 71, 75
Pelosina cylindrica, ii. 60
rotundata, ii. 60
Planispirina bucculenta, ii. 42, 60
var. placentiformis, ii. 43
sphera, ii. 59
Polymorphina oblonga, ii. 67, 75
Polystomella crispa, li. 71, 75
Pullenia quinqueloba, ii. 45, 69
Pulvinulina elegans, var. partschiana, ii. 70
oblonga, ii. 46
Reophaa dentaliniformis, ii. 63, 75
longiscatiformis, ii. 63, 75
murrayana, li. 63, 75
spiculifera, ii. 62, 75
Saccammina spherica, ti. 61, 75
Spiroloculina canaliculata, ii. 57
Truncatulina, ii. 27
haidingeri, ii. 45
lobatula, ii. 33, 41, 45, 69, 75
refulgens, ii. 27, 33, 41, 45, 69
tenera, ii. 70
Uvigerina angulosa, ii. 32, 41, 44, 68
pygmed, li. 68, 75
Valvulina fusca, ii. 64
INDEX 249
Foraminifera—continued
Virgulina schreibersiana, ii. 27, 30, 65, 75
subsquamosa, ii. 27, 30
Fosse, i. 178
Mt. Erebus, i. 210, 212
Fossil ice of Ross Barrier, i. 44
wood, Beardmore Glacier, i. 120, 121, 248, 249,
256, 315
Fossils, i. 311
Foyaite, Fiji, 1. 307
Framheim, i. 11, 20, 22, 31, 127, 131, 132, 138, 300
movement of ice, i. 129, 131
winds, i. 23, 31
Franklin Island, i. 5
French Antarctic Expedition, 1903-4, i. 303
Front Door Bay, C. Royds, i. 177
Frost-weathering, i. 194, 199, 206, 207
C. Royds, i. 263
Ferrar Glacier Valley, i. 194, 195
Fry Glacier, i. 46, 64, 77, 78
Valley, i. 77
width of, i. 140
Fumaroles, C. Bird, i. 218
Deception Island, i. 304
Mt. Erebus, i. 212, 213, 215
Fungus, Blue Lake, i. 160
Green Lake, i. 151
Stranded Moraines, i. 97
Farthest South journey, i. 16
GappBros, i. 244, 245, 246, 299, 303, 308; ii. 132,
227
bronzite, Depot Island, i. 246
C. Trizar, i. 50, 66
Galapagos Group, i. 306
Garnet, i. 110, 233; ii. 161, 169, 205, 206, 219, 232
Garwood, Professor, i. 5, 241, 315
Gases given off from algal deposits, Coast Lake, i. 164
Green Lake, i. 153, 154
Round Lake, i. 165
Terrace Lake, i. 168
by thio-bacteria, ii. 6
Gasteropoda, ii. 85
Capulus subcompressus, ii. 86
Eulima convexa, ii. 86
Lovenella antarctica, ii. 86
austrina, li. 86
Odostomiopsis major, ii. 86
Retusa frigida, ii. 86, 88
Rissoa adarensis, ii. 86
deserta, ii. 86
fraudulenta, ii. 86
gelida, ii. 86
glacialis, ii. 86
Scissurella euglypta, ii. 85
Thesbia innocens, li. 86
Trophon longstaffi, 1. 86
priestleyi, ii. 86, 87
Turbonilla polaris, ii. 86
Valvatella crebrilirulata, ii. 85
minutissima, ii. 85
250 INDEX
Gasteropoda—continued Glaciers, Alpine type, i. 45, 77, 140, 142, 173
Valvatella refulgens, ii. 85 ancient extension of, i. 285-90
Vermicularia murrayi, ii. 86 beheaded, i. 45
Gaston Islet, i. 285 cirque, i. 82, 120
Gauss Antarctic Expedition, i. 50, 303 cliff, i. 45, 93
Gaussberg, i. 286, 290 corrie, i. 45, 119, 120
Geikie, A., i. 312 cétiéres, i. 45
Geikie Inlet, i. 48, 50, 52, 64 cwm, i. 45
Glacier, i. 64 dune, i. 45, 105
soundings, i. 63 encaissés, i. 45
Geographic Pole, i. 14 Greenland type, i. 45
Gerlache massif, i. 82 hanging, 1. 45, 92, 93
Strait, i. 285, 286, 298, 303, 317 inlet, i. 118
Geysers, i. 5, 217 Norwegian type, i. 45, 107, 140, 142, 146
Gibraltar Straits, i. 317 of Antarctic horst, i. 46
Gilbert, S. K., i. 45 movement of, i. 141
rirvanella incrustans, i. 241 outlet, i. 45, 46, 77, 86, 87, 117, 118, 122, 129, 133,
“* Gitter-struktur,” ii. 169 140, 141, 142, 173, 200, 201
Glacial erosion, i. 120, 201 Piedmont, i. 45
fiord, i. 115 plats, i. 45
* flood-gauge,”’ Mt. Hope, i. 119 recemented, i. 45
gravel, i. 83 reconstructed, i. 45
groove, C. Royds, i. 79, 148, 194 spillway, i. 45, 87
sandstones of South Australia, i. 196 tributary, i. 122
transportation, i. 206 Glaciology, i. 45-192
upthrust, i. 276 summary, i. 192
valley, i. 82, 83, 109 Glass, ii. 102, 107, 109, 112, 113, 116, 117, 124, 135, 137,
Glaciation, C. Royds, i. 108 138, 142, 143, 144, 220
Graham Land, i. 314 Glauconitic sandstone, Nansen-Drygalski Piedmont,
maximum at Drygalski Barrier, i. 62, 63 i. 316
at Granite Harbour, i. 83 Glen Roy, parallel roads, i. 207
at west slopes, Mt. Erebus, i. 106, 111 Glossopteris, 1. 311, 312
Mt. Hope, i. 120, 121 Gneiss, i. 8, 234
of Europe, i. 145 C. Roberts, i. 82, 232
past and present, i. 102 C. Ross, i. 78
Ross Island, i. 102 C. Royds, i. 232
South America, i. 314 Dry Valley, i. 233
Turk’s Head, i. 106 Falkland Islands, i. 298
trend of, i. 109 Kukri Hills, i. 232
waning, i. 116 Mackay Glacier Valley, i. 201
Glacier between Capes Lyttleton and Goldie, width of, near C. Ross, i. 79, 80
i. 140 porphyritic, C. Royds, i. 111
fans, i. 137, 138, 139, 144, 173 erratic, Ross Island i. 102, 263
jetty, i. 103, 134, 138, 139, 142, 146 South Neptune Islands, i. 232
ribs, i. 137, 138, 144, 146 Gneissic granite, i. 48, 66
runners, i. 146 Beardmore Glacier, i. 232
Shackleton Inlet, i. 140 C. Roberts, i. 232
Skelton Inlet, i. 140 C. Ross, i. 78, 80
Tongue, i. 102-6 near C. Ross, i. 79, 80
aground or afloat, i. 103, 105, 106 Depot Island, i. 78, 80, 244, 246, 300, 308
crevasses, i. 103 Dunlop Island, i. 83
description of, i. 103 Mt. Crummer, i 244
marine erosion, i. 207 near C. Irizar, i. 233; ii. 230
soundings, i. 105, 106 Gneissification, i. 233
Glacier-ice erosive power, i. 102, 109, 118 Goddard, E. J., Professor, i. 248, 249, 315
faceting power of, i. 63 Gondwana coal-measures, i. 253, 255
Ferrar Glacier, i. 89 Land, i. 291
origin of, i. 98 rocks, i. 247, 250, 298, 300, 315
plasticity, i. 93 Upper, i. 313
Ross Barrier, i. 135, 173 Goorkha Craters, i. 301
structure of, i. 114, 132; ii. 16 Gordon, W. T., Dr., 1. 312
INDEX
Gourdon, E., i. 1, 45, 246, 286, 297, 299, 303, 304, 311
Graham Land, i. 2, 3, 286, 290, 300, 302, 303, 309, 310,
314, 317, 318
summary of stratigraphical sequences, i. 314
Granite, i. 4, 8, 48, 77, 78, 79, 244, 245, 303, 309;
ii. 210, 211, 212
Alaska, i. 304
Beardmore Glacier, i. 232, 245
biotite-allanite, i. 65
biotite-hornblende, i. 4, 64
C. Bernacchi, i. 84, 234
Trizar, i. 50, 64, 65, 66, 233, 245, 246, 308; ii. 210
Ross, i. 78
near, i. 79, 80
Royds, i. 80, 109, 111, 133, 149, 262, 264
Drygalski Barrier, i. 55, 56
Dunlop Island, i. 83, 84
East Fork, i. 94
epidotic, i. 84
erratic, C. Royds, i. 108, 111, 112
erratics, Backdoor Bay. i. 263
granophyric, C. Royds, i. 110
Gregory Point, i. 80
grey, i. 245
C. Royds, i. 111
Green Lake, i. 150
Mt. Erebus, i. 111
intrusion into dioritic rock, i. 245
dolerite, i. 245
King Edward VII Land, i. 309
Lower Glacier Depot, i. 119, 235
Mackay Glacier Valley, i. 201
Marble Point, i. 84, 233, 247
near, i. 84
Mt. Crummer, i. 204, 245
Hope, i. 265
Larsen, i. 245, 246, 308
Murray, i. 69
pink, i. 64, 245, 246, 250
red, i. 80, 111
reddish porphyritic, Drygalski Barrier, i. 55
Ross Island, erratic, i. 102, 117, 263
Solitary Rocks, i. 87, 88
South Victoria Land, i. 260
specific heat of, i. 17
white, i. 4, 84, 309
Granite Harbour, i. 12, 30, 78, 81, 82, 86, 115, 119, 191,
232, 233, 234, 243, 250, 288, 298
“alb” valleys, i. 200
height of mountains at back of, i. 64
soundings, i. 115
trogtal valleys, i. 200
Granite porphyry, i. 244, 246, 309
Grano-diorite, i. 4, 299, 308, 309
Granophyre, i. 244, 245
C. Royds, i. 110
Depot Island, i. 246
Granophyric granite, C. Royds, i. 110
porphyry, i. 244
Granular ice crystals, South Magnetic Pole plateau,
i. 40, 41
i)
or
=
Granular ice crystals—continued
from snow, i. 40, 41, 94
Great Ice Barrier, i. 40
Granulation, i. 61
Ross Barrier, i. 145
Granulites, i. 111, 233, 257; ii. 161; see also Pyroxene
granulites
Graphite, i. 84, 233; ii. 195, 231
Graptolites, i. 312
Gravels, Blue Lake, i. 159, 161
Dunlop Island, i. 83, 84
Gravity differentiation, ii. 117
Great Ice Age, i. 146
Barrier (see also Ross Barrier), i. 9, 24, 31, 32,
46, 63, 98, 117, 121, 301
afloat, i. 123, 125
at Beardmore Glacier, i. 116, 121
former, C. Royds, i. 109
movement of, i. 111
moat, i. 116, 117
temperature, i. 16, 40
undulations, i. 123
treen Lake, i. 148, 149, 150, 151, 164, 165; ii. 6
ablation, i. 33, 34
algal deposit, i. 151, 153, 157, 278, 279
brine, i. 152, 153, 154; ii. 6
analysis of, ii. 7
contraction cracks, i. 150
convexity of surface, i. 151
dimensions of, i. 150
gas from algal material, i. 153, 154
ice, i. 152, 153
salinity of, ii. 7
Priestley’s shaft, i. 149, 152
structure of ice, i. 151, 152, 153, 154, 183 ; 1. 7
summer thaw, i. 2038, 204
temperature in trenches, i. 151, 153, 154
temperatures of water, i. 169
of commencement of freezing, ii. 7
thickness of ice, i. 152, 154
thio-bacteria in, ii. 5
trenches, i. 151, 152, 154
Greenland glaciers, i. 45
seter, i. 207
western, i. 3, 46
Greenlandic type of valley, i. 8
Gregory, J. W., Professor, i. 310, 311, 319
Gregory Point, i, 78, 80, 81
Groénland Expedition, i. 32, 45
Grooves in granite, C. Royds, i. 108, 109
in kenyte lava, C. Royds, i. 263
in sea-floor, North Sea, i. 146
in sea-ice, i. 178
Guano, analysis of, i. 283, 284
C. Royds Rookery, i. 191, 197
commercial value of, i. 284
Gulf of Mexico, tectonic lines, i. 297
Guthrie, F. B., i. 280, 283; ii. 6, 89
Hamatire, i. 199; ii. 108, 120, 137, 182
Halle, i, 299, 311
252
Halleflinta-like porphyries, i. 244
Hallett’s Cove, South Australia, i. 242
Hallman, E. F., i. 231, 272, 273
Halysites, i. 239
Hanging glaciers, i. 45, 92, 93
valleys, i. 8, 200, 201
js Ferrar”Glacier Valley, i. 201
Terra Nova Bay, i. 201
Hann, i. 1, 20, 22, 25, 32, 202
Hansen Nunatak, i. 48, 57, 287
Harbord Glacier, width of, i. 140
Ice Tongue, i. 46, 64, 69, 71
area, 1. 69
Harbour Heights, i. 222
Harker, Alfred, Dr., i. 304, 305, 306; ii. 146
Harriman Alaska Expedition, i. 45
Hatcher, J. B., i. 299
Hawthal, R., i. 299
Heart Lake, i. 167
Heart of the Antarctic, i. 117, 188, 204, 217, 230, 231
Heathcoatian series, Victoria, 1. 243
Hedley, C., i. 266, 269, 272, 274, 276; ii. 85
Heiberg Glacier, i. 2, 132, 146
Heim, i. 45
Heinrich, T. O., i. 281
Hepworth, Commander, j..12, 20
High Hill, i. 150
“ High-level ” sea breeze, i. 27
High Peak, i. 150
Himalayas, i. 317
Hinde, G. J., Dr., i. 242, 243
Hobbs, W. H., Professor, i. 25, 32, 101
Hochlandeis, i. 45
Hodgson, i. 224
Holland, ii. 146, 158
Holothurians, i. 231
Hood Glacier, i. 8
Hope Bay, i. 286, 299, 300, 301, 311, 312, 315, 318
Hornblende, i. 218, 233, 245, 260, 303 ; ii. 102, 119, 173,
176, 178, 180, 217, 224
basaltic, ii. 109, 119, 124, 132, 140
cossyrite-like, Mt. Cis; 1. 257
diorite, Cathedral Rock, i. 232
dyke rocks, C. Irizar, i. 66
schists, Cathedral Rocks, i. 232
Hornblende-lamprophyres, C. Irizar, i. 50, 64
Hornblendic-lamprophyre, C. Ross, i. 78
Horseshoe Bay, i. 108, 109, 112, 114, 191
description of glacier, i. 112
Horst; see Antarctic horst
within a horst, i. 23, 86, 98
Hot Springs, i. 13
Deception Island, i. 304
Hughes Bay, i. 285
Hurley, C. F., i. 61, 202
Hut, C. Royds, i. 150, 166
Point, i. 5, 15, 16, 27, 83, 104, 123, 181, 185, 208,
222, 223, 259, 276
blizzard wind, i. 104
erratics, i. 264
raised beach, i. 274
INDEX
Hyades, Dr., i. 299, 304
Hydrometer, Buchanan, ii. 3
Hypabyssal rocks, i. 246
Hypersthene, ii. 109, 112, 118, 119, 124, 132, 144, 157,
227
gabbros, Depot Island, i. 246
Ickr-AGE, maximum thickness of ice, 1. 290
Ice-apron, i. 46, 151
Ice, Antarctic, 1. 101
barrancas, i. 54, 62, 76
bund structure in sea-ice, i. 42, 44
ealotte, C. Irizar, i. 65
caps, 1. 45
cascades, Turk’s Head, i. 226
eave, Turk’s Head Glacier, i. 106
Tce-cliff, C. Barne, i. 108
Ferrar Glacier, i. 92
Glacier Tongue, i. 103
Horseshoe Bay, i. 112
Ross Barrier, shape and height of, i. 130
Solitary Rocks, i. 88
Ice convex surface, C. Barne, how formed, i. 166
coralloidal, i. 159, 169; ii. 11, 18, 15
cracks, Butter Point, i. 99
C. Barne, i. 166
C. Trizar, i. 66
C. Royds, i. 186
Coast Lake, i. 90, 163-65
Ferrar Glacier, i. 89, 90
crystalline, i. 88, 89, 92, 155
crystallisation from a concentrated vapour, ii. 19
an attenuated vapour, ii. 19
vapour, li. 18
crystals from snow, i. 40, 41
granular, i. 40
hexagonal, ii. 21
on dredging-line, i. 112, 183
trigonal symmetry of, ii. 19
Ice-cut facets, Mt. Hope, i. 121
shelf near Lower Glacier Depot, i. 120
Ice discharge from Victoria Land, i. 141
divide, i. 23, 122
dongas, i. 54, 62
erosion, i. 8, 9, 108, 199
evaporation, i. 35, 40, 41, 42
Tce-falls, David Glacier, i. 201
Ferrar Glacier, i. 88, 89, 90, 93, 201
Mackay Glacier, i. 81, 201
near Mt. Bartlett, i. 201
Mt. Buckley, i. 122, 201
Mt. Darwin, i. 201
Solitary Rocks, i. 88
Tce, fast, i. 46, 180
fibrous structure, i. 153, 177, 183
Ice-fields, Magnetic Pole plateau, i. 60
Ice, floating, i. 46
Tce-flowers, i. 41, 42, 177, 181, 182; ii. 20
development and origin of, i. 42, 181, 182, 183 ;
ii. 20
Tce-foot, i. 207
Backdoor Bay, i. 191
Blacksand Beach, i. 177, 178, 179, 190
Blue Lake, i. 158
C. Barne, i. 219
Royds, i. 175, 176, 177, 179, 180
definition of, i. 175
erosion of, i. 176, 177
Frontdoor Bay, i. 177
Hut Point, i. 185
Inaccessible Island, i. 224, 225
McMurdo Sound, i. 184
Tent Island, i. 225
thaw effect, i. 176
Ice, enamel-like, ii. 7, 9, 10
fossil, i. 44
frost spicules, ii. 21
gases in, i. 152, 153, 154, 164, 165, 168
granulation, i. 45, 61, 94, 132
hexagonal, i. 183, 193; ii. 21
Blue Lake, i. 155, 156, 159, 160, 161
Clear Lake, i. 155
Ferrar Glacier, i. 88, 89, 92, 155
inland-, i. 45, 114
jetties, i. 145, 146
lake-, i. 45, 151
laminated, i. 184
land-, i. 45
Ice-leaves, ii. 10
Tce lenticles, i. 89, 96
mean density of Barrier Ice, i. 143
mechanical disruption of, i. 190, 191
methods of study of the crystalline fabric,
ii. 3
moss, i. 35, 36
odoriferous, ii. 15
pancake, i. 181, 182, 183
parting, position of, i. 3
plasticity of, at Butter Point, i. 99
plates and blades, ii. 16, 19, 21
prismatic, i. 151, 155, 156, 159, 160, 161, 162,
169, 176, 193; ii. 7, 10, 12, 15, 16
raft, i. 145
recrystallisation of, ii. 21
ribs, i. 137, 138, 139
ridge near Bay of Whales, i. 188
rippled, C. Barne, i. 166
Coast Lake, i. 162
saline vaporisation of, ii. 18
scales with trigonal symmetry, ii. 19
sea-, i. 45, 46
shrinkage of, i. 133
Ice-slabs, i. 45, 98
Ice slopes, Mt. Buckley, i. 121
snow-dune, i. ]01
specific heat of, i. 18
spiracle, i. 35, 36
stalactites, i. 178; ii. 18
cross-section, ii. 17
drip from, ii. 17
grotesque forms, ii. 18
INDEX 253
Ice—continued
structure of, Blue Lake, i, 155, 156, 159, 160, 162 ;
ii. 11
Clear Lake, i. 155, 156: ii. 15
Coast Lake, i. 162, 164, 165; ii. 15
Green Lake, i. 152, 153, 154, 164; ii. 7
Round Lake, i. 165; ii. 8
Shallow Lake, ii. 10
Sunk Lake, i. 169
Terrace Lake, i. 168
sublimation of, ii. 18
undulation, i. 184
vesicular, i. 132
Icebergs, i. 45, 46, 141, 170, 173, 177, 180
aground between C. Royds and C. Barne, ry ives
174, 183, 186
C. Bernacchi, i. 172
classes of, i. 173
encountered by S.Y. Nimrod, i. 170, 171
etched by sun’s rays, i. 172
from Glacier Ice, i. 172
King Edward VII Land, i. 171
grooves in, i. 132, 172
limit of drift, i. 146
marine erosion of, i. 207
structure, i. 132, 133, 170, 171, 172
tabular, i. 132, 133, 170, 174
transporting power, 1. 98
Turk’s Head Glacier, i. 106
Ichthyopteryx gracilis, i. 314
TIcicles, Butter Point, i. 99
club-shaped, Blacksand Beach, i. 178
Iddings, i. 305
Timenite, ii. 109, 155, 177
Tnaccessible Island, i. 191, 224, 257
height of, i. 289
Inclusions, allomorphous, homologous, ii. 147
antilogous, ii. 147
dolerite (altered), ii. 143
enallogenous, i. 221; ii. 147
gabbroid nodules in basalt, ii. 131, 132
homeceogenous, il. 147
hornblendic in trachyte, C. Bird, ti. 140
Observation Hill, ii. 140
origin of, ii. 141
in igneous rocks, il. 131, 146
Ross Island, i. 5, 208, 221, 307,
308 ; ii. 131
classification, ii. 145
conclusions, ii. 147
summary, ii. 147
in minerals, gas, li. 178
liquid, ii. 178
methods of microscopic investigation, ii. 131
microsanidinite in basic rock from Hut Point, ii. 138
in kenyte, C. Royds, Inaccessible Island and
Tent Island, ii. 136
in trachyte, Mt. Cis, ii. 134
origin of, ii. 139
olivine nodules in basalt, ii. 131, 132
orbicular augite-syenite, ii. 142
254
Inclusions—continued
plagioclase-pyroxene in trachyte, Mt. Cis, ii. 143
plesiomorphous antilogous, ii. 147
homologous, ii. 147
pneumatogenous, ii. 147
polygenous, endopolygenous, ii. 147
exopolygenous, ii. 147
pyroxene, ii. 131, 132
quartz-bearing, ii. 144
quartz-pyroxene in trachyte, Mt. Cis, ii. 144
sanidinite, in erratic, C. Royds, i. 138
in kenyte, C. Royds, Inaccessible Island and
Tent Island, ii. 136
in trachyte, Mt. Cis, ii. 134
C. Crozier, ii. 131
origin of, ii. 139
Inland forts, i. 86, 87
Inland ice, i. 45, 116, 121, 122, 133
structure of, i. 114
snow, structure of, i. 61
Inlet Glacier, i. 118
TInsolation, effect of, i. 199
International Geological Congress, Stockholm, 1910,
i. 275, 276
Intrusive rocks, South Victoria Land, i. 308
Inversion of temperature, i. 17
in Ross Sea, i. 12, 13
Tran Ranges, i. 317
Trish peat, analysis of, i. 281
Tron ores, titaniferous, C. Royds, i. 111, 246
phosphide, Mt. Hope, i. 289
pyrites, i. 233
Islands, ice-covered, i. 138
Isle Adelaide, i. 2
Islet Lake, C. Royds, i. 167
trend of axis, i. 109
Itacolumite, i. 52
James Ross Island, i. 317, 318
Japanese Expedition, i. 4, 171, 298
Jasper, radiolarian, i. 312
Jensen, H. I., Dr., i. 114, 218, 220, 257, 259, 260, 261,
307, 309 ; ii. 89
Joyce, i. 127, 133
Jurassic, i. 5, 299, 301, 306
flora, i. 312, 313
New Zealand, i. 314
K @RSUETITE, 1. 257
Katapeiric, ii. 94
Kataphorite, ii. 106
Kaiser Wilhelm II Land, i. 286, 292
Kaolin, ii. 205
Kar Terrace, i. 200
Kare, i. 45
Karroo, i. 6
dolerite intrusions, i. 256
quartz dolerites, i. 308
Keltie Glacier, i. 8
Kenyte, i. 309; see Petrological descriptions
Blacksand Beach, i. 177, 179
INDEX
Kenyte—continued
Blue Lake, i. 112, 157, 158, 159, 161, 169
bosses, C. Royds, i. 148
C. Barne, i. 167, 195, 219, 220, 259
Roberts, i. 82
Royds, i. 98, 108-12, 149, 175-77, 180, 195,
199, 202, 218, 226, 227, 229, 263
Clear Lake, i. 112, 154, 155, 156
Coast Lake. i. 163
line, C. Barne to Horseshoe Bay, i. 108
Deep Lake, i. 167, 168
Dry Valley, i. 95
East Fork, Ferrar Glacier, i. 94
erratic, Pony Lake, i. 111
Granite Harbour, i. 98
Green Lake, i. 150
Inaccessible Island, i. 224, 225
leaching of, i. 147, 148, 166
Mt. Cis, i. 259
Erebus, i. 111, 210, 212, 220, 221, 257, 258
Penguin Rookery, i. 191
Pony Lake. i. 166
Ross Barrier, i. 103
Island, i. 102, 307
Skuary, i. 107, 226, 227, 228, 259
spheroidal weathering, C. Royds, i. 199
Stranded Moraines, i. 97
Sunk Lake, i. 167, 169
Tent Island, i. 225, 259
Terrace Lake, i. 166
Tuff Cone, i. 221
Turk’s Head, i. 224, 226, 227, 259
weathering of, i. 195, 198
Western Mountains, i. 198
Kenyte-tuff, C. Royds, i. 111, 196
Mt. Erebus, i. 111
Keraunoids, ii. 117
Kermadec Deep, i. 302
Kerosene shale, i. 311
Kersantite dykes, C. Irizar, i. 65, 245, 308
Kersantites, i. 244, 246, 308, 309; ii. 220
King Edward VII Land, i. 2, 4, 11, 12, 19, 30, 126, 131,
135, 142, 145, 171, 180, 298, 309,
310, 314, 319
discovered, i. 123
icebergs, i. 171
ocean currents, i. 188, 189
Plateau, sastrugi, i. 22
snowfall, i. 29
Oscar II Land, i. 286, 290, 317
Kleinschmidt, i. 306
Knob Head Mountain, i. 195, 197
Keettlitz Glacier, i. 4, 86, 201, 234, 242, 264
width of, i. 140
Konga diabase, i. 308
Kukri Hills, i. 88, 232
Kulaite, i. 114, 218, 260; ii. 221
Lasoratory, Low-temperature, li. 3, 19
Labradorite, ii. 109, 113, 116, 117, 133, 158
Lacroix, Professor A., i. 8307; ii. 131, 146
INDEX
Lady Newnes Bay, i. 5, 6
Lake, Backstairs Passage Glacier, i. 187, 188
bed, Stranded Moraines, i. 97, 98
Lake-ice, i. 45, 147, 152; ii. 4
classification of crystalline structures, ii. 16
Lakes, i. 147, 148
C. Royds, i. 108, 109, 147, 148, 149, 201
life in, ii. 13
saline constituents of, ii. 6, 10
summer thaw, i. 203
trend of axes, i. 109
Ferrar Glacier, i. 91-94
glacial erosion of, i. 201
Mt. Erebus, i. 210
Ross Barrier, i. 207
Island, i. 102
saltness of, i. 147, 148; ii. 4
Lamellibranchiata, ii. 86
Adacnarca nitens, ii. 86
Cardita astartoides, ii. 86
Kellya nimrodiana, ii. 86
[Lima hogsoni, i. 273; ii. 86
Pecten colbecki, i. 95, 231, 266, 273, 275, 276; ii. 86
Philobrya limoides, ii. 86
Tellimya antarctica, li. 86
Thracia meridionalis, ii. 86
Lamplugh, G. W., i. 267, 269, 296
Lamplugh Island, i. 64, 265, 288
Lamprophyre, i. 64, 78, 244, 246
Land-ice, i. 45, 171
moraines, i. 194
La Plata River, i. 292
Larsen, Capt., i. 311
Larsen-Gerlache-Crummer Massif, i. 57
Larsen Glacier, i. 29, 46, 48, 50, 56, 57, 61, 62, 137, 191,
269, 270, 287
area of, i. 57, 61
effect of thaw, i. 204, 205, 206
width of, i. 140
massif, i. 82
Piedmont, i. 48, 61
Lashley Mountains, i. 114
Laurie Island, i. 312
Lava and tufts of Erebus, i. 257-61
trachytic, Mt. Cis, i. 221
Lavas, C. Royds, i. 194
Dry Valley, i. 223
Hut Point, i. 222
Ross Island, i. 208, 223
Lawson, A., Professor, i. 315
Leaching of kenyte, i. 147, 148
action, Western Mountains, i. 148
Lelapia spicule, i. 239, 240
Lemberg’s solution, ii. 189
Lepeta antarctica, i. 266
Lepralia, i. 231, 273
cheilodon, i. 266
Lesser Antilles, i. 304
Leucite, i. 219, 227, 257, 259, 309; ii. 94, 104, 106, 110,
138
Leucitophyres, i. 257, 309; ii, 111
II
Leucoxene, ii. 177, 179
Lhertzolite, ii. 134
Lichens, C. Royds, i. 229
Liege Island, i. 285
Lima, i. 273
Limburgites, i. 309
Hut Point, i. 259
Mt. Erebus, i. 257
Observation Hill, i. 259; ii. 116
Limburgitic dolerite, C. Bird. i. 218
Lime, carbonate, i. 199
Lime-soda felspars, i. 246
Limestone, i. 48, 242; ii. 189
altered, i. 8
Archeocyathine, i. 5
argillaceous, Ferrar Valley, i. 247, 248
Backdoor Passage, 1. 242
breccias, Beardmore Glacier, i. 234, 241
Lower Glacier Depot, i. 235; ii. 190
Buckley Island, i. 241, 242
Cambrian, i. 234, 235
Mts. Buckley and Bartlett, i. 121
C. Royds, i. 111
Cloudmaker, i. 120
crystalline, i. 234
Drygalski Barrier, i. 55
Dunlop Island, i. 241, 242
Mt. Hope, i. 119, 242, 289
Nansen, i. 242
oolitic, i. 235
red, Beardmore Glacier, i. 242
Stranded Moraine, i. 243
Limonite, i. 199, 226; ii. 132
Liothyrina, i. 231
antarctica, i. 266
Little Razorback, i. 225
Liv Glacier, i. 131, 142
Louis Philippe Land, i. 230
Lovenella antarctica, i. 266
Lower Cambrian Rocks, South Australia, i. 242
Lower-carboniferous, i. 249
Lower Glacier Depot, i. 119, 289, 315
cliffs, i. 118, 119, 120, 235
Lower-miocene, i. 313
Lower-ordovician, i. 243
Lyothyrina, i. 231
Lyssacine hexactinellid, i. 240
Mactntosu, Lieut., i. 114, 127, 133, 135, 218
Mackay, Dr., i. 35, 54, 83, 230
Mackay Glacier, i. 46, 64, 81, 82, 86, 101, 119, 201, 288
289, 298 :
movement of, i. 141
Valley, i. 201, 316
width of, i. 140
Macquarie Islands, i. 318, 319
Madigan, C. T., i. 317
Madre de Dios Archipelago, i. 297
Magellan clay, South America, i. 314
Magellanic Archipelago, i. 297
Magnesium salts, i. 198, 199
20
256
Magnetic Pole, i. 16, 17, 18, 26
Party, i. 46, 54
Plateau, i. 17, 18, 23, 24, 25, 27, 28, 29, 31, 57,
60, 61, 187, 202, 207
altitude, i. 60
crevasses, i. 60
highest temperature, i. 40, 41
ice-crystals, i. 40, 41
ice-falls, i. 60
icefields, i. 60
snowfields, i. 60
winds, i. 22, 28, 31, 61
Magnetite, i. 220, 227, 258, 259; ii. 94, 103, 108, 109,
111, 112, 113, 116, 117, 119, 124, 132, 135,
137, 138, 142, 162
basalt, C. Barne, i. 259
Tent Island, i. 259
Malacolite, ii. 167
Malaspina Glacier, i. 9
Marble partly silicified, C. Royds, i. 111
saccharoidal, C. Bernacchi, i. 84, 233, 234, 242, 247
C. Royds, i. 111
Stranded Moraines, i. 233
Point, i. 84, 233, 247
Marine deposits, i. 210, 230, 231
erosion, i. 4, 9, 71, 74, 137, 201, 207
near Backdoor Bay, i. 207
C. Barne, i. 207
C. Washington, i. 207
checked by sea-ice, i. 192
Drygalski Ice Tongue, i. 207
Flagstaff Point, i. 207
Glacier Tongue, i. 207
Icebergs, i. 207
near C. Bird, i. 207
Nordenskjéld Ice Tongue, i. 207
Ross Barrier, 1. 207
Stranded Moraines, i. 98
fossils, Dry Valley, i. 85
Mt. Hope, i. 121
muds, i. 266
Backstairs Passage, i. 266
Dry Valley, i. 266
Drygalski Barrier, i. 55, 56, 62, 63
elevated, C. Royds, ii. 41, 49, 85
from soundings, i. 55
geological age of, i. 273
Mt. Erebus, i. 208, 210
Ross Island, i. 231, 266
Sea, i. 192
South Victoria Land, i. 231
Southern Ocean, i. 192
upthrust hypothesis, i. 270, 275
near Mt. Larsen, ii. 27, 37
western slopes, Ross Island, i. 266
sediments, Backdoor Bay, i. 262
C. Barne, i. 262, 263
Marshall, Eric, Dr., i. 118, 121, 218
P., Dr., i. 306, 307
Marshall Mountains, height, i. 122
Marston, i. 127, 133
INDEX
Martin, L., i. 9
Mawson, Douglas, i. 2, 19, 33, 42, 45, 48, 54, 61, 65, 68,
78, 81, 114, 153, 154, 160, 161, 165, 208, 212,
217, 218, 232, 233, 234, 243, 245, 247, 251,
254, 260, 277, 302, 308, 311; ii. 89, 203
Classification of Eruptive Rocks, i. 244
Contribution to Study of Ice-structures, ii. 1
Petrology of South Victoria Land Rocks,
ii. 201
Mawson Glacier, i. 46, 64, 69, 71, 74, 76, 101, 201, 288, 289
“alb” valleys, i. 200
trogtal valleys, i. 200
Valley, i. 76
width of, i. 140
Mawson’s Expedition, i. 202, 317
McGillan, i. 114, 218
McMurdo Sound, i. 5, 8, 9, 10, 11, 12, 15, 16, 23, 86, 96,
98, 102, 107, 109, 111, 112, 115, 181, 132,
133, 173, 179, 181, 186, 190, 276
blizzards, i. 42, 106
currents, i. 189, 190
east side, soundings, i. 109, 115
floe-ice, i. 180
freezing of water, i. 182, 189
marine erosion, i. 207
moraine material, i. 115, 116
sediments, i. 199, 230
temperature of water, i. 188
thaw effect, i. 190
thickness of ice, i. 182
water sky, i. 190
Meinardus, i. 22, 25
Meridional fault, i. 5
Mesozoic, i. 298, 310
Meta-arkoses, Beardmore Glacier Valley, i. 234
Meta-granites, Beardmore Glacier Valley, i. 234
Metamorphic rocks, i. 247
Marble Point, i. 233, 247
Metamorphism, i. 250
C. Trizar, i. 65
Metasomatism, ii. 190
Meteorological notes, i. 14
Mica, biotite, i. 251
green, near C. Ross, i. 80
muscovite, i. 251
Mica-schist, Dry Valley, i. 233
Marble Point, i. 84, 233
Ross Island, i. 263
Mickle Island, i. 191
Microcline, ii. 169, 207
Micro-granite, i. 246
Microlites, ii. 112, 116, 117, 136
Micropegmatite, i. 255, 308
Microperthite, ii. 158, 172
Microsanidinites, i. 221; ii. 134, 136, 139
Microtinites, i. 308; ii. 134
Microzoa, ii. 76
Blue Lake, i. 161
Midget Tarn, i. 167
Mill, H. R., Dr., i. 15, 22
Mill Glacier, i, 8, 121
INDEX
Minchin, i. 240
Minerals. See under Specific Titles
Minette, i. 110, 244, 246; ii. 176
Mingaye, J. C. H., i. 250, 277
Minna Bluff, i. 5, 6, 22, 31, 32, 115, 116, 117, 125, 127,
129, 133, 135, 136, 139, 141, 143, 289
Miocene, i. 299, 306
Graham Land, i. 314
Lower, i. 201, 314
plant beds, i. 311 >
South America, i. 314
Mirabilite, i. 168, 271, 272, 277
analyses of, i. 277, 278
Mite, Blue Lake, i. 161
Moat, Drygalski Glacier, i. 50
Great Ice Barrier, i. 116, 117
Mollusca, i. 231; ii. 85; see Lamellibranchiata and
xasteropoda
Monzonites, 1. 303
Moose Island, i. 285, 286
Moraine Hill, i. 167
Moraines, i. 262
Backdoor Passage, i. 242, 270
Beardmore Glacier, i. 120, 121, 235, 242, 264, 265
between White and Black Islands, i. 271
Black Island, i. 116
Blue Lake, i. 112, 157, 158, 159
Brown Island, i. 116
C. Bernacchi, i. 84
Trizar, i. 265
Royds, i. 109-12, 117, 148, 176, 193, 194, 218,
221, 262, 264
Clear Lake, i. 155, 156
Cloudmaker, i. 120, 236
Cora Island, i. 276
Deep Lake, i. 168
Dry Valley i. 95, 98, 233, 262
Drygalski Barrier, i. 55, 56, 62, 63, 139, 204
East Fork, Ferrar Glacier, i. 94, 98, 262
englacial, Reeves Glacier, i. 56, 89, 173
Ferrar Glacier, i. 86, 87, 89, 90, 93, 94, 155, 195,
197, 199, 233, 262, 287
Glacier Tongue, i. 106
Green Lake, i. 150
Tnaccessible Island, i. 225
land, i. 194
McMurdo Sound, i. 96, 97, 98, 109, 115, 116
Minna Bluff, i. 289
Mt. Discovery, i. 289
Erebus, i. 110, 111, 114, 133, 208, 210, 262, 276
Hope, i. 265
Morning, i. 289
Terror, i. 287, 288
Nansen-Drygalski Piedmont, i. 316
near Buckley Nunatak, i. 248, 264
C. Armytage, i. 264
Crozier, i. 133
Ross, i. 79
Mt. Larsen, i. 245
New Harbour, i. 115
Nordenskjéld Ice Tongue, i. 76
Moraines—continued
Pinnacle ice, Ross Barrier, i. 116, 184
Reeves Glacier, i. 56, 57
Rock Terrace, i. 69
Ross Barrier, i. 103, 110, 115, 116, 136, 144, 223,
262
Island, i. 114, 117, 262, 288
Skuary, i. 107, 227
supraglacial, i. 173
Terrace Lake, i. 168
upthrust, i. 275, 276
Wilson Piedmont, i. 100
Moreno, T. P., i. 299
Moss Ice, i. 35, 36, 52, 53
Drygalski Ice Barrier, i. 52
Mosses, i. 229
Mossman, R. C., i. 12
Mt. Adams, i. 315
height of, i. 122
Bartlett, i. 120, 201, 289
height of, i. 121
Baxter, i. 60
height of, i. 48
Bellinghausen, i. 48, 50, 82, 252, 287
Bird, i. 5, 102, 208, 318
geyser, i. 217
glaciation, i. 102, 103
Bowen, i. 208
Buckley, i. 120, 122, 201, 289
former height of ice, i. 121
height of, i. 121
Chetwynd, i. 100, 201
height of, i. 76
Christensen, i. 318
Cis, i. 194, 210, 220, 221, 259
erratics, i. 221
lava, i. 221
seree, i. 194, 220
trachyte, i. 257
Creak, i. 100
Crummer, i. 48, 60, 82, 244, 245, 271, 272, 287
avalanches, i. 199, 204
granite, 1. 204, 245
height of, i. 57
terraces, i 201, 275
Darwin, i. 120, 201, 241, 289
height of, i. 121
Davidson, i. 9
height of, i. 64
Davis, i. 114
Discovery, i. 6, 9, 115, 116, 127, 289, 301, 318
height of, i. 224
Dorman, height of, i. 122
Erebus, i. 4, 5, 6, 9, 11, 13, 16, 17, 18, 22, 23, 25,
26, 27, 64, 97, 104, 108, 110, 111, 114,
115, 118, 123, 125, 133, 134, 208, 241,
262, 318
ascent of, in March 1908, i. 103, 190, 211
eruptions, i. 215, 216, 217, 218, 220
fourth crater, i. 214, 215
fracture, i. 86, 208, 222
258
Mt. Erebus—continued
glaciation, i. 103, 106, 107, 111, 112
height of, i. 215, 224
lavas and tufis, i. 257-61, 307; ii. 93
classification of, ii. 94
sequence of, ii. 118
lichens, i. 229
névé fields, i. 112
oldest crater, i. 210, 215
petrology, ii. 93
plain of glassy ice, i. 118
raised beaches, i. 111, 274
schistose erratics, i. 98
second crater, i. 210, 212, 213, 214, 258
snowfall at second crater, i. 213, 214
terraces, i. 44, 110, 111
third crater, i. 214
third and fourth craters, i. 210, 212
winds, i. 22, 26, 27, 104, 105, 216
Mt. Fridtjof Nansen, i. 6, 300
height of, i. 298
Gauss, i. 69-71
George Murray, i. 69, 71, 99, 293
Gerlache, i. 48, 50, 60, 252, 287
Haddington, i. 318
height of, i. 223
Herschell, i. 318
Hope, i. 118, 120, 121, 289
erratics, i. 119, 120, 242
granite, i. 265
height of, i. 119, 289
ice-cut facets, i. 121
moraines, i. 120, 265, 289
shelf, i. 121
Howard, i. 65, 67, 69
Huggins, i. 23
Ida, i. 289
Judd, i. 208
Kenya, Central Africa, i. 218
K. Olsen, i. 2
Kirkpatrick, height of, i. 122
Larsen, i. 24, 26, 28, 48, 50, 57, 60, 63, 82, 118, 252,
276, 287, 290
granite, i. 245, 246, 308
height of, i. 287
marine deposits, 1. 230, 273, 274
Lindenburg, i. 304
Lister, i. 8
height of, i. 115, 298
Mackintosh, i. 60, 208, 218
Marshall, height of, i. 122
Melbourne, i. 6, 48, 50, 60, 318
height of, i. 224
Morning, i. 115, 289, 301, 318
height of, i, 223
Murray, i. 69, 76
Nansen, i. 3, 4, 5, 6, 17, 23, 24, 27, 50, 57, 60, 64,
86. 121, 140, 200, 242, 252, 290, 293,
300
crevasses, i. 37
height of, i. 48, 64
INDEX
Mt. Neumeyer, i. 50, 252, 287
Priestley, i. 48, 50, 82, 208
Smith, i. 69
Terra Nova, i. 5, 6, 208, 318
fracture, i. 86, 208, 217
Terror, i. 6, 125, 208, 217, 262, 287, 288, 318
fracture, i. 86, 208
height of, i. 224
Wild, height of, i. 122
Mud flats, Dry Valley, i. 95
Mulock Inlet, i. 117
Glacier, width of, i. 140
winds, i. 23, 24
Murray, James, i. 11, 12, 42, 151, 161, 169, 188, 203,
204, 217, 218, 225, 229, 266
Muscovite, ii. 189, 231
NANSEN PrepMmont, i. 48, 54, 55, 57, 61, 62
length of, i. 62
Nansen-Drygalski Piedmont, i. 316
Natal quartz-dolerites, i. 308
Nathorst, A. G., Professor, i. 267, 312
National Antarctic Expedition, 1901-4, i. 5, 12, 20, 35,
81, 84, 86, 132, 1385, 141, 210, 215, 222, 224, 225, 232,
255
Natrolite, ii. 102
Neobuccimum, i. 231
Nepheline, i. 257, 260, 309 ; ii. 99, 100, 109
basalt, i. 307
syenite, i. 307
Nephelinite, Raiatea, i. 307
Névé, i. 135, 170, 172
Blue Lake, i. 157, 158
fields, i. 6, 61, 104, 121, 130, 133
Mts. Buckley and Bartlett, i. 121
granular, i. 89
Mt. Erebus, i. 107, 112
Ross Barrier, 1. 144
structure of, ii. 11
Neweastle coal-measures, i. 255
New Caledonia, i. 306
yuinea, i. 305
Harbour, i. 84, 86, 92, 98, 100, 206, 234
algal deposit, 1. 283
dimensions, i. 115
dried-up lake beds. i. 199
lava, i. 208
Hebrides, i. 306
South Wales timber, products of dry distillation,
i, 281, 282
Zealand, i. 299, 302, 305, 306, 307, 310, 314
penguin, i. 314
Plateau coal-measure, i. 316
tectonic trend lines, i. 319
Zealand-Chatham Islands Plateau, i. 318
Newer Paleozoic, i. 250
Nilssonia, i. 313
Nimrod, i. 17, 95, 103, 105, 109, 115, 127, 130, 131, 132,
170, 172, 175, 180, 181, 188, 190, 218
held up by pack-ice, i. 191
Nipple, Blue Lake, i. 158
INDEX 259
Nodules, Ferrar Glacier Valley, i. 198 Ordovician fossils, i. 312
Nordenskjéld, Otto, Dr., i. 2, 246, 285, 286, 297, 299, rocks, i. 247
301, 303, 304 Orleans Channel, i. 286, 298
Nordenskjéld Expedition, i. 291, 311, 313 Orthoclase, i. 55, 251, 259, 260, 267, 303; ii. 109, 155,
Ice Barrier Tongue, i. 12, 46, 64, 69, 71, 74, 76, 100, 157, 169, 170, 209, 211
103 Orthophyre, Mt. Cis, i. 257
afloat, i. 74 Ostracoda, i. 231, 266, 269, 272, 274; ii. 37, 49, 55,
marine erosion, i. 207 71
structure of, i. 74 bathymetric distribution of, ii. 76
North and South fault near C. Adare, i. 5 |Aglaia obtusata, ii. 71
Fork Glacier, i. 86, 101, 115, 288 Bairdia, ii. 49
Pole, i. 14, 20 victrix, li. 49
winter temperature, i. 20, 22 Cythere, ii. 37, 49
Sea, i. 145, 146 davisi, ii. 72, 75
Barrier, i. 145 foveolata, ii. 38, 49, 72
Piedmont, i. 146 norman, ii. 50, 73
Northern Foothills, i. 98 parallelogramma, ii. 38, 50
Hemisphere, i. 14 polylrema, ii. 50
Party, i. 84, 101, 172, 190, 199, 201, 232, 242 quadriaculeata, ii. 73
Solitary Rock, i. 88 Cytherideis, li. 37
Northumbria, i. 146 levata, ii. 39
Norwegian glaciers, i. 45, 107, 140, 142, 146 Cytheropteron, ii. 37
Nosean, i. 257; ii. 104, 106, 112, 115 antarcticum, li. 38
Nunatak, i. 48, 57, 88 Cytherura, li. 49
Beardmore Glacier, i. 122 costellata, ii. 49, 51
Blue Lake, i. 158 obliqua, ui. 73
Buckley Island, i. 120 rudis, ii. 74, 75
Framheim, i. 127 Loxoconcha, ii. 49
Mackay Glacier, i. 81 mawsoni, ii. 50
Mt. Bartlett, i. 120, 121, 201 Pontocypris, li. 37
Buckley, i. 120, 121, 122, |201 faba, ii. 71
Darwin, i. 120, 121, 201 subreniformis, i. 37
Ross Barrier, i. 102 Xestoleberis, ii. 49
Island, i. 110 davidiana, ii. 51, 73
Turk’s Head Glacier, i. 106 setigera, ii. 73
variegata, li. 73
Oamaru beds, i. 314 Otozamites, i. 313
Oates Land, i. 293 “ Outlet ” glacier valleys, i. 8, 201
Observation Hill, i. 185, 222, 257, 259, 264 Outlet glaciers, i. 45, 57, 60, 61, 77, 86, 87, 100, 101, 117,
height of, i. 289 118, 122, 129, 133, 140, 142, 173, 200, 201
Ocean currents, i. 137
C. Royds, i. 189 Pachypteris, i. 313
Ross Sea region, li. 188, |189, '190 Pachyteryx grandis, i. 314
Oleandridium, i. 313 Pacific type of rocks, i. 3, 299, 304, 305-11, 319
Oligocene, i. 299, 313] Pack-ice, i. 180, 191
Graham Land, i. 314 Paleontological evidence, i. 299, 311
South America, i. 314 Paleozoic, i. 243, 308
Oligoclase, ii. 100, 140, 141, 142, 169 slates, i. 310
Olivine, i. 221, 227, 258, 259 ; ii. 102, 103, 108, 112,113, Palagonite, C. Barne, i. 167
114, 115, 116, 132, 135, 136, 137, 138, Tuff, i. 228
183 Palissya, i. 313
basanites, C. Bird, i. 218 Palmer Archipelago, i. 317
Olivine-bearing basalts, i. 196 Land, i. 317
and dolerites, C. Bird, i. 114 Pancake-ice, i. 181, 182, 183
Olivine-kenyte, East Fork, Ferrar Glacier, i. 94 “ Panzer-horsts,” i. 298, 318
Olivine phenocrysts, i. 112, 219 Para-gneisses, i. 158
Oolites, silicified, C. Royds, i. 150, 242; ii. 191 Parallel road, C. Bird, i. 114, 275
Oolitic limestone, C. Royds, i. 111, 150 Glen Roy, i. 207
silicified, South Australia, i. 242 Parana beds, C. Fairweather, i. 299, 314
Opacite, ii. 101, 104, 109, 115 Northern Argentine, i. 314
Opal, ii. 182 South America, i. 314
260
Parasitic cones, C. Barne, i. 218, 258
C. Royds, i. 218
Mt. Erebus, i. 194, 208, 210, 213, 220, 221, 222,
252
Skuary, i. 107, 258
voleanic cone, C. Bird, i. 114
“ Parting of the winds,” i. 24, 25
Patagonia, i. 295, 296, 300, 304, 311, 317
Patagonian Andes, i. 299
molasse, i. 299, 314
Paths in moraines, C. Royds, i. 110
Paulet Island, i. 304, 318
Peat, algal, i. 44, 147, 229, 230, 278
analysis of, i. 280, 281
of Irish peat, i. 281
deposits, Coast Lake, i. 280
Dry Valley, i. 278
Pecten colbecki, i. 95, 231, 266, 273, 275, 276
Pecten conglomerate, i. 299, 314
Graham Land, i. 314
Pegmatite, i. 68, 234, 244, 246; ii. 169, 219
C. Roberts, i. 232
Ross, i. 78
Royds, i. 110
Pelites of South Victoria Land, ii. 208
Penck Glacier, i. 46, 64, 77, 78
width of, i. 140
Peneplains, i. 6, 8, 64
Penguin Rookery, C. Royds, i. 183, 186, 191
Penguins, i. 314
Pennell, Lieut., i. 144, 317
Penninite, ii. 178, 180, 182
Peridotites, i. 308
Permo-carboniferous, i. 250, 254, 255, 298, 311, 312
glacial sandstones of India and Australia, i. 196, 251
of South Africa and South America, i. 251
Tasmania, i. 250, 298
Peru, i. 300
Petrographical character of eruptive rocks, i. 299, 303—
311
Petrological descriptions :
Andesite, augite, C. Barne, ii. 112
Amphibolite, Ferrar Glacier, ii. 126
Aplite, C. Irizar, ii. 219
C. Royds erratic, ii. 170
Arkose. Beardmore Glacier, ii. 206
Basalt, C. Barne, ii. 116
dense porphyritic, C. Royds erratic, ii. 182
enstatite olivine, Crater Hill, ii. 113
felspar olivine, C. Royds, ii. 113
kulaitic, C. Bird, ii. 120
limburgitic, Hut Point, ii. 114
magma, Tent Island, ii. 116, 117
magnetite, C. Barne, ii. 116
olivine, ii. 113
Basanite, Crater Hill, ii. 113
olivine, C. Bird, ii. 125
Camptonite, C. Ross, il. 235
Chert, ferruginous, Cloudmaker, ii. 195
Conglomerate, Ferrar Glacier, ii. 204
Diabase, porphyritic, C. Royds erratic, ii. 179
INDEX
Petrological descriptions—continued
Diorite, biotite hornblende, Mt. Larsen, ii. 225
mica, Depot Island, ii. 237
quartz, C. Royds erratic, ii. 173
sphene biotite hornblende, Mt. Larsen, ii, 224
C. Trizar, ii. 226
Dolerite, alkaline, C. Bird, ii. 125
C. Bernacchi, ii. 229
Bird, ii. 125
limburgitic, C. Bird, ii. 125
quartz, aphanitic, ii. 157
porphyritic, ii. 156
Dunite, biotite, ii. 132
hornblende, ii. 132
Gabbro, bronzite, Lower Moraines, McMurdo Sound,
ii. 227
hornblende, ii. 132
hypersthene, Dry Valley, ii. 227
Gneiss, actinolite, C. Royds erratic, ii. 183
tremolite, C. Royds erratic, ii. 183
Granite, basic inclusions of, ii. 223, 237
biotite, Mt. Larsen, ii. 212
porphyritic, Beardmore Glacier, ii. 214
epidotised, south of C. Ivizar, ii. 230
foliated, Depot Island, ii. 236
gneissic, south of C. Irizar, ii. 230
hornblende biotite, C. Irizar, ii. 210
metamorphosed, ii. 230
muscovite biotite, Beardmore Glacier, i. 213
porphyry, aplitic, C. Irizar, ii. 217
granophyric, C. Royds erratic, ii. 174
Kukri Hills, ii. 215
Granophyre, C. Royds erratic, i. 175
Granulite, ii. 161
pyroxene, acid, C. Royds erratic, ii. 162, 163, 164,
165
basic, C. Royds erratic, ii. 167, 168
scapolite bearing, C. Royds erratic, ii. 165,
166
Kenyte, acid, The Skuary, ii. 105, 106
agglomerate, Turk’s Head, ii. 108
basic, C. Royds, i. 108
plagioclase, Turk’s Head, ii. 108
porphyritic (shonkinitic), C. Royds erratic, ii.
109
vitrophyric, C. Barne, ii. 107
The Skuary, ii. 106
with secondary epidote, The Skuary, ii. 106
Kersantite, C. Irizar, 1. 220
Kulaite, C. Bird, ii. 124
Mt. Bird, ii. 121
Leucitophyre, Ross Island, ii. 111
Limburgite, basanitic, C. Barne, ii. 116
Observation Hill, ii. 116
Limestone breccia, Cloudmaker, ii. 81, 189
dolomitic, Beardmore Glacier, ii. 190
dolomitic, Cloudmaker, ii. 190
Dry Valley, ii. 195
Dunlop Island, ii. 195
East Fork, Ferrar Glacier, ii. 194
impure, Beardmore Glacier, ii. 196
INDEX
Petrological descriptions—continued
Limestone, oolitic, C. Royds, ii. 192
Cloudmaker, ii. 191
dolomitised, ii. 193
silicified, ii. 194
recrystallised, Cloudmaker, ii. 194
Marble, ii. 195, 231
Microsanidinite, Ross Island, ii. 134
Microtinites, Ross Island, ii. 136
Minette, C. Royds erratic, ii. 176, 177
Pegmatite, C. Royds erratic, ii. 169
Phonolite-trachyte, C. Royds erratic, ii. 102
Phyllite, Beardmore Glacier, ii. 208
C. Royds erratic, ii. 185
Porphyrite, augite, C. Ross, ii. 235
C. Royds erratic, ii. 178
Porphyry, felspar, C. Royds erratic, ii. 176
orthoclase, Stranded Moraines, ii. 215
quartz, Mt. Larsen, ii. 215
uralite, Dry Valley, ii. 227
Sandstone, Beacon, ii. 204
micaceous, C. Royds erratic, i. 186
Sanidinite, Ross Island, ii. 134, 136, 138
Schist, actinolite, C. Royds erratic, ii. 184
quartz, C. Royds erratic, ii. 185
spotted, C. Royds erratic, ii. 185
tremolite, C. Royds erratic, ii. 185
Slate, Beardmore Glacier, ii. 208
Solvsbergite, C. Royds erratic, ii. 179
Syenite, augite (orbicular), C. Barne erratic, ii. 142
C. Royds erratic, ii. 171
sodalite, C. Royds erratic, ii. 172
with Wohlerite, C. Royds erratic, ii. 171
Tephrite, leucite, Crater Hill, ii. 111
Trachydolerite, breccia, Parasitic Cone, Mt. Erebus,
ii. 109
Inaccessible Island, ii. 110
leucite, Parasitic Cone, ii. 110
Trachyphonolite, C. Bird, 1. 119
Trachyte, alkali (baked), Tuff Cone, Ross Id., ii. 101
alkaline, C. Bird, i. 119
anorthoclase, erratic, Ferrar Glacier, ii. 102
C. Royds erratic, ii. 101
biotite hornblende, C. Royds erratic, ii. 102
corundum-bearing, C. Royds erratic, ii. 181
hornblende (phyro), C. Bird, ii. 119
kersuetite <girine-augite, Observation Hill, ii.
101
oligoclase, Parasitic Cone, Mt. Erebus, ii. 100
phonolitic, C. Royds erratic, ii. 102
Inaccessible Island, ii. 102
Mt. Cis, ii. 99, 100
sapphire bearing, C. Royds erratic, ii. 189
spherulitic, C. Royds erratic, ii. 182
Vosgesite, C. Royds erratic, ii. 177
Philippi, E., Dr., i. 50, 286, 303, 305, 309
Phlogopite, ii. 186
Phonolite, C. Barne. i. 167
Dunedin, i. 306
Mt. Erebus, i. 257
Raratonga, i. 307
261
Phonolites, i. 309
Phonolitic trachyte, Inaccessible Island, i. 257 ; ii. 102
Mt. Cis, i. 257
Phyllite, C. Royds, i. 111; ii. 185
Phyllocarids, i. 312
Physiography, Ross Sea region, i. 3
Pie-crust snow, i. 37
formation of, i. 38, 39, 40, 117
Great Ice Barrier, i. 37, 39, 40, 140
Nordenskjéld Ice Barrier Tongue, i. 37
on sea-ice, i. 37
plateau south of Beardmore Glacier, i. 39
Ross Barrier, i. 117
Piedmont afloat, i. 45, 46, 122, 137, 138, 184
aground, i. 9, 45, 67, 69, 76, 78, 79, 80, 84, 135, 138
Butter Point. i. 98, 99
coastal, i. 68, 69, 98, 99, 121
Drygalski-Reeves, i. 46, 135, 136, 138
fanned out, i. 145
glaciers, i. 45, 66, 67, 68, 71, 77, 78, 79, 83, 84, 96,
98, 99, 100, 101, 138, 188
Horseshoe Bay, i. 112
ice, i. 173, 184, 199
structure of, i. 132
on land, i. 45, 201
Reeves-Larsen glaciers, i. 61
Wilson, i. 99, 100, 101
* Pinnacled ice,” McMurdo Sound, i. 37, 38, 116, 182,
184, 185, 190
Pistacite, ii. 178
Plagioclase, i. 259, 303, 304; ii. 132, 137, 154, 156, 170,
73s Palit
Plain of glassy ice, i. 118
Plains, coastal, i. 8, 9
Plateau coal-measure formation, i. 316
snow, i. 19, 26, 28
wind, i. 23, 24, 26-28, 74, 76, 90, 92, 100, 101, 189,
195, 197, 198
Mt. Erebus, i. 190
Pleistocene Ice Age, i. 145
Pleonaste, ii. 132, 133
Pliocene, i. 292, 314
Graham Land, i. 314
South America, i. 314
Plutonic rocks, i. 246
Poikilitic, ii. 10, 102, 166, 167, 173
Polar cyclone, i. 31
Polyzoa, i. 231; ii. 41, 55
Backstairs Passage, i. 231, 266
C. Barne, i. 274
cellaria, li. 41
Pony Lake, i. 166
ablation, i. 33
area, i. 166
summer thaw, i. 203
Pools, unfrozen sea-water, i. 13
Porphyries, i. 94, 110, 244; ii. 176, 215, 227
Porphyrite, i. 111, 244; ii. 141, 178, 235
Porphyritic granite, Backstairs Passage, i, 267
Post-Cambrian, i. 241, 244
Post-Cretaceous, i. 291
262 INDEX
Post-Gondwana, i. 244, 291
Post-Jurassic, i. 315
Post-Mesozoic, i. 299
Post-Pliocene, i. 291
Post-Tertiary lavas, i. 309
Pot-holes, Ferrar Glacier Valley, i. 197-98
Pourquoi Pas Expedition, i. 301
Pram Point, i. 102, 131
Pre-Cambrian crystalline complex, i. 5
rocks, i. 232, 233, 234, 244, 247, 298
GC. Bernacchi, i. 84, 85, 233, 247
Precipitation, C. Royds, i. 34, 44
Ross Barrier, i. 145
Pre-Devonian, i. 8
Pre-glacial history of South Victoria Land, i. 291-96
Pre-Gondwana, i. 244, 260
peneplain, i. 8
Pressure ridges, i. 54, 55
Blacksand Beach, i. 177, 179, 190
C. Barne, i. 108
Crozier, i. 102, 129
Royds, i. 185, 186
McMurdo Sound, i. 184
Mt. Terror, i. 125
near Framheim, i. 129
Pram Point, i. 102
Ross Barrier, i. 127, 129, 130, 131, 132, 138,
139, 144, 146
Prestrud, Lieut., i. 4, 129, 309
Priestley, R. E., i. 37, 41, 48, 64, 77, 85, 88, 110, 132,
185, 201, 233, 258, 263, 269, 273, 274, 277, 283, 315 ;
ii. 89, 93, 148, 168, 189, 204, 208
Priestley Glacier, i. 48, 135, 137
coal-measures, i. 315
Massif, i. 82
Peak, i. 158
shaft, Blue Lake, i. 36
Green Lake, i. 149
Prince Luitpold Land, i. 319
Prior, G. T., Dr., i. 218, 227, 232, 234, 247, 255, 256, 303,
305, 309; ii. 94, 126, 153, 158, 209, 210
Prior Island, description of, i. 66
height of, i. 288
Protective action of ice and snow, i. 5
Protopharetra, i. 237, 238, 239, 240, 315
dubiosa, i. 235, 239, 240
radiata, i. 235, 238, 240
rete, 1. 235, 238, 239
retezona, 1. 238, 240
Psammites of South Victoria Land, ii. 204
Psephites of South Victoria Land, ii. 204
Pseudo-leucite, ii. 101, 103, 106, 110, 111
Pterophyllum, i. 301, 313
morrisianum, i. 313
Pumice, Mt. Erebus, i. 212, 213, 214, 215, 222
Pyrite, ii. 164, 166, 186, 195, 218, 220, 231
Pyrotherium-Notostylops beds, South America, i. 314
Pyroxene, i. 111, 255, 257, 259, 303; il. 155, 166
granulites, acid, ii. 162
basic, ii. 162, 167
characters of ii. 162
Pyroxene granulites—continued
divisions of, ii. 162
scapolite bearing, ii. 162, 165
monoclinic, ii. 162
rhombic, ii. 132
Pyroxene-perthite, ii. 154
Pyroxenites, i. 308
QuaRTz, i. 111, 233, 235; ii. 144, 162, 165, 169, 171
Quartz-diorite, i. 4, 244, 309
C. Royds, i. 110
schists, i. 4, 309
Quartz dolerite, British Guiana, i. 256, 308
Clear Lake, i. 112
Finger Mountain, Ferrar Glacier Valley, i. 255
Mackay Glacier Valley, i. 201
Natal and Zululand, i. 256, 308
New York, i. 256, 308
Northern Brazil, i. 308
petrological character of, i. 255
sills, i. 6, 112, 250, 255, 298, 307, 308, 309
Tasmania, i. 250, 256
South Africa, i. 255, 291, 308
America, i. 255
Victoria Land, i. 308
Southern Hemisphere, i. 291
Tasmania, i. 255, 256, 291, 308
Venezuela, i. 308
pebbles, i. 248
porphyries, i. 246, 267, 308, 309
porphyry, i. 244, 263
schist, i. 234
Quartzite, C. Royds, i. 111, 246, 262, 264
enclosures, near Depot Island, i. 78, 244
Ross Island, i. 263 -
Quaternary, Graham Land, i. 314
South America, i. 314
Queen Alexandra Range, i. 6, 116
Maud’s Range, i. 2, 3
RaprATion, Ferrar Glacier, i. 91
Radiolaria, ii. 56
Radiolarian rock, i. 242, 316
oolites, resembling, ii. 192
Raised beaches, i. 4, 62, 82, 95, 266, 275, 276, 316;
ii. 85; see also Marine muds
Backdoor Bay, i. 111, 114, 269, 273, 274, 275
Backstairs Passage, i. 266, 267, 269, 270, 274
C. Bird, i. 114
Dry Valley, i. 95, 273
Graham Land, i. 314
Hut Point, i. 274
South America, i. 314
Spitzbergen, i. 267, 269
marine deposit, Backstairs Passage, i. 266, 267, 269,
270
Dry Valley, i. 266
Ross Island, i. 266, 269, 270, 289, 290
Raratonga, i. 307
Razor-back, i. 225
INDEX 263
Red Flag Hill, i. 150
Lake, i. 167
Reeves Glacier, i. 23, 24, 29, 46, 48, 55, 56, 57, 60, 61, 62,
118, 135, 137, 140, 141, 287
crevasses, i. 57
dimensions, i. 57, 61
maximum glaciation, 1. 63
movement of, i. 141
width of, i. 140
Nunatak, i. 287
Piedmont, i. 48, 56, 61, 62, 201
Reinschia australis, i. 312
Reiter, A., i. 299, 305
Relief Inlet, i. 18, 52, 54, 56, 62, 63, 116
soundings, i. 63
thickness of ice at maximum glaciation, i. 63
Research for future expeditions, i. 144, 145, 146
Rhabdocyathus, i. 239, 240
Rhetic plant-bearing beds, i. 298
Riebeckite, i. 257; ii. 94, 97, 106, 108, 111
Rink, H., i. 45
Rio Grande do Sul Gondwana coal-measures, 1. 253
Robertson, Capt., i. 312
Robertson Island, i. 318
Robertson’s Bay glaciers, i. 134, 135
Roches moutonnées, i. 50, 194
Rock basins, i. 102, 200
collections, numbering of, ii. 133
descriptions ; see Petrological descriptions
flour, C. Royds, i. 110
shelf, Mt. Hope, i. 121
terrace, i. 69, 122, 271
Rogers, i. 291
Rookery, i. 203
Roosen Channel, i. 286
Ross, J. C., Sir, i. 12, 46, 123, 125, 130, 131, 133, 143,
188, 215, 287
Ross Barrier (see also Great Ice Barrier), i. 2, 3, 4, 9, 11,
12, 14, 20, 22, 23, 30, 46, 56, 63, 83,
84, 100, 101, 104, 105, 106, 116,
117, 118, 122, 146, 166, 173, 192,
263, 276, 288, 291
afloat, i. 123, 125, 126, 127, 134, 135, 138, 142,
144
aground, i. 138, 144, 146, 188
altitude, i. 4, 82, 102, 137
annual ice accumulation, i. 139, 142, 143
snow accumulation, i. 135, 139, 142, 143
boring through ice, 1. 144, 145
C. Royds, i. 108, 134
control specimens, i. 139, 140, 145
cross-section of, i. 135, 136, 142
depth of water, i. 138
description of, i. 123, 125-35
direction of currents beneath, i. 145, 188, 189
east and west valleys, i. 127
effect on C. Bird erratics, i. 114
erosive force, i. 115
extent when discovered by Sir J. C. Ross,
i. 287
formation of, i. 138, 139
II
Ross Barrier—continued
fossil ice, i. 44
future observations of, i. 144, 145, 146
granulation and crystallinity, i. 145
greatest height, i. 136
thickness, i. 136
height at Western Inlet, i. 130
near Beardmore Glacier Outlet, i. 120
horizontal shrinkage of, i. 133, 144
icebergs, i. 171, 180
Tce Cliff, shape and heights of, i. 130-34, 137,
138, 142
ice discharged on from west side Ross Sea,
i, 141
lost annually, i. 139, 143
ribs, i. 137, 138, 144
internal structure, i. 131, 132, 133, 138, 139
lakes, i. 207
least thickness, i. 138
length, i. 46, 142
marine erosion, i. 207
maximum glaciation, i. 133-35, 144, 146, 228,
289
date of latest phase, i. 143
mean density of ice, 1. 143
moraines, i. 103, 110, 116, 117, 144, 223, 262,
290, 293
movement of, i. 125, 127-30, 135, 136, 138,
141, 142, 146
per year, i. 135, 142
origin of, i. 132-37
pie-crust snow, i. 117
“pinnacle ice,” i. 116
plain of glassy ice, i. 117, 118
rate of movement of, i. 145
remains of, i. 210, 263, 270
retreat of, i. 103, 112, 131, 133, 134, 144, 145,
287
from 1842 to 1902, i. 133, 144, 287
sastrugi, i. 118
sea-ice, i. 144
serial temperatures in ice, i. 145
temperature of sea-water, i. 137, 138, 188
thickness of, i. 138, 142, 144, 290
undulations, i. 123, 124, 129, 130, 136, 137,
138, 144, 185
vertical shrinkage, i. 133, 134, 143, 144, 290
Ross Island, i. 3, 4, 5, 8, 9, 11, 12, 22, 27, 82, 110,
114, 115, 117, 133, 146, 157, 196, 260,
309
lavas and tuffs, i. 208, 223
petrology of, ii. 93
marine deposits, i. 230, 231, 266, 289, 290;
ii. 27, 37, 41, 49, 53, 85
moraines, i. 117, 133, 262, 288
submergence of, i. 223
terrace, i. 102
types of glaciation, i. 102
winds, i. 22, 27, 189
Piedmont, i. 145
quadrant, i. 1
264
Ross Sea, i. 2, 3, 4, 6, 9,11, 14, 18, 23-27, 30, 31, 46, 50,
61, 100, 101, 122, 134, 135, 138, 139, 141,
148, 173, 180, 200, 213, 221, 232, 292
annual ice discharge into, i. 141
average density of water, i. 143
boulders, i. 194
cross-section glaciers west side of, i. 140
currents, i. 11, 12, 139, 188, 189, 190
dimensions, i. 11
down-throw fault, i. 109
freezing of, i. 190
marine erosion, i. 207
moraines, i. 293
region, physiographic characteristics, i. 3, 4,
139
sea-ice, i. 139
sediments, i. 199, 230; ii. 27, 37, 41, 49, 53, 85
soundings, i. 11, 63, 144; ii. 53
temperature, i. 11, 12, 13, 17, 139, 143, 188
winds, i. 23, 26, 27, 28, 31, 50, 61, 62, 196
Roth, S., i. 299
Rotifera, i. 156, 161, 229, 231, 278
Round Lake, i. 158, 165; ii. 8
algee, i. 165
structure of ice, i. 165; ii. 8
temperature in trench, i. 165
of water, i. 169
thickness of ice, i. 165
Royal Company Islands, i. 302
Society Range, i. 3, 6, 22, 23, 86, 98, 234, 288, 293,
298, 300
height of, i. 64, 86
Royds, C. W. R., Lieut., i. 123, 125
Russell, I. C., i. 9
Rutile, i. 251; ii. 205, 206
SAGENITE, ii. 177
Sagenopteris phillipsi, i. 312, 313
Salicifolia, i. 313
Salt carried by wind, i. 148
efflorescence, Dry Valley, i. 95
Range, i. 317
water pool, C. Armitage, i. 184
San Jorge series, South America, i. 314
Sand-blast action, i. 195, 197, 198
Sandstone, i. 5; ii. 186, 204
Adelie Land, i. 317
carbonaceous, i. 121, 248
Devonian, i. 311
Drygalski Barrier, i. 55
Dry Valley, i. 233
Ferrar Valley, i. 247, 248
glauconitic, i. 316
Lower Glacier Depot, i. 235
metamorphosed, Mt. Cis, i. 257
Mt. Nansen, i. 242
Plateau, i. 6
pot-hole, weathering of, i. 197, 198
Sandwich Group, i. 302, 308, 312, 317
Sanidine, ii. 135, 136, 137, 181
INDEX
Sanidinites, i. 221, 257; ii. 134, 136
Santa Catarina Basin, thickness of coal, i. 253, 254
permo-carboniferous rocks, i. 313
system, i. 298
Cruz beds, South America, i. 314
Sapphire, i. 111; ii. 108, 180
bearing trachyte, C. Royds, i. 111
Sarconeurum glaciale, i. 229
Sastrugi, i. 22, 23, 24, 26, 29, 37, 61, 101, 185
Beardmore Glacier, i. 118
Drygalski Ice Barrier, i. 50, 51, 52
Ferrar Glacier, i. 92
Glacier Tongue, i. 104
height of, i. 202
Magnetic Pole Plateau, i. 61, 202
McMurdo Sound, i. 37, 101
Mt. Erebus, i. 212, 214
Nordenskjéld Ice Tongue, i. 74
ramp, i. 24
Ross Barrier, i. 118
Sawadowski Island, i. 312
Scandinavia, i. 145, 295, 296
Scapolite, i. 111; ii, 168, 165
Schetalig, J., i. 4
** Schiller ” structure, ii. 171
Schistose erratics, Mt. Erebus, i. 98
Schists, i. 8; ii. 184, 185
C. Bernacchi, i. 84, 234
Royds, i. 111
Dry Valley moraines, i. 233
East Fork, Ferrar Glacier, i. 94
Marble Point, i. 84
Ross Island, i. 102
South Georgia, i. 312
“* Schlieren,” ii. 177
Schorl, C. Irizar, i. 66
Scleropteris, i. 312
Scott Island, i. 302
Scott, R. F., Capt., i. 3, 11, 13, 22, 26, 29, 30, 52, 64, 107,
123, 125, 130, 133-37, 143, 201, 215, 223, 224, 227,
241, 287, 298, 315
Scottish National Antarctic Expedition, 1902-4, i. 12,
230
Oceanographical Laboratory, i. 230
Scott’s Depot A, movement of, i. 125, 127, 129
snow deposition at, i. 133, 143
Expedition, i. 46, 48, 64, 105, 141, 201, 208; see
also British Antarctic Expedition
Farthest West, i. 114
last expedition, i. 201
Nunatak, i. 4, 309
southern journey, i. 125
Screes, C. Barne, i. 193
Royds, i. 193, 194
Ferrar Glacier Valley, i. 195
Mt. Cis, i. 194, 220
Turk’s Head, i. 225, 227
Scrivenor, J. B., i. 299
Sea-ice, i. 45, 46, 171, 173, 175, 176, 177, 178, 180, 182,
183, 192; ii. 16
Backdoor Bay, i. 175, 176
INDEX
Sea-ice—continued
banded structure, i. 183
Bay of Whales, i. 190
Blacksand Beach, i. 178, 179
break-up of, i. 187, 188, 190, 191
bund structure, i. 42
C. Barne, i. 108
effect on littoral fauna, i. 192
on temperature, i. 192
Ferrar Glacier, i. 89
formed in calm water, i. 181, 183
importance of, i. 192
MeMurdo Sound, i. 179, 182, 183, 184, 187, 190
mechanical disruption of, i. 190, 191, 192
Ross Sea, i. 139, 144, 187
salinity of, ii. 16
stratification of, i. 184
thaw effect, i. 187
thickness of old, i. 185
transporting power of, i. 192
Sea-spiders, Dry Valley, i. 95
Sea-water, specific heat of, i. 18
temperature, 1. 188
Seal breathing-holes, i. 139, 190
Islands, i. 301
Sedimentary formation, i. 77
rocks, i. 247, 316
Beardmore Glacier, i. 150
Sefstrém Glacier, i. 269, 276
Senkungsfeld of Ross Sea, i. 4, 221, 301
Senonian, Graham Land, i. 314
South America, i. 314
Sentinel Peak, i. 157
Seracs, Drygalski Ice Barrier, i. 50
Sericite, ii. 154, 162, 165, 179, 185, 208, 232
Serpentine, ii. 99, 102
Serpulze, Backdoor Bay, i. 273
Backstairs Passage, i. 231, 266, 267
Glacier Tongue, i. 105, 231, 273
Ross Island, i. 231
Serra Geral, Gondwana coal-measures, i. 253
Seter of Scandinavia and Greenland, i. 207
Seymour Island, i. 313, 317, 318
beds, i. 314
Shackleton, Sir Ernest, i. 3, 6, 19, 22, 39, 40, 116, 117,
118, 127, 129, 130, 131, 201, 224, 241, 315; ii. 93
Shackleton Expedition, 1908, i. 127, 248, 287, 300, 315 ;
see also British Antarctic Expedition
Inlet, i. 22, 117, 125, 130, 289
Shackleton’s Farthest South, i. 116, 122, 292, 293
Shale, kerosene, i. 311
Shallow Lake, ii. 9
ice-structures, ii. 10
section, li. 9
Shaw, W. N., Dr., i. 14
Shelf-ice, i. 171, 173
Shell beds, marine, C. Barne, i. 110
Shetland Island, temperature. ?. 22
Shingle, Dunlop Island, i. 83
Shiraze, Lieut., i. 4, 171, 298, 309
Shore drift, i. 98
265
Siberia, i. 14
Sierra de Cordoba, Gondwana coal-measures, i 253
Nevada of California, i. 304
“ Sieve ” structure, ii. 165, 183
Silicification, ii. 189, 191
Sil, Finger Mountain, i. 255
Minna Bluff, i. 117
Sillimanite, ii. 142, 145
Sills, i. 6, 64, 81, 112, 245, 250, 254, 298
Simpson, G. C., Dr., i. 31
Siphonema areaceum, i. 241
incrustans, i. 241
Skager Rak, i. 145
Skeats, E. W., Professor, i. 235, 242, 243, 315; ii. 189
Skelton Inlet, i. 86, 117, 141, 142
Skua gulls, i. 274, 275
Skuary (see also C. Evans), i. 107
cones, i. 107, 228, 258, 259
description of, i. 107, 108, 227
eskers, i. 107, 228
Slate, i. 8; ii. 208
calcareous, Dry Valley, i. 233
C. Adare, i. 310
Cloudmaker, i. 243
Smithsonian Physical Tables. i. 17, 18
Snow accumulation on Ross Barrier, i. 135, 143
amount equal to rainfall, i. 143
Snow-apron, i. 131
Snow-bergs, i. 171, 173, 186; ii. 18
structure of, i. 171-74
Snow cornice, i. 71
Blacksand Beach, i. 178, 179
Butter Point, i. 98
Drygalski Ice Barrier, i. 51, 52
Glacier Tongue, i. 103
crusts, i. 37-40
formation of, i. 38-40
Great Ice Barrier, i. 39, 40
on plateau south of Beardmore Glacier, i. 39
crystals, i. 19; ii. 19
dune ice, i. 101
theory, i. 100, 101, 105
granular, Ferrar Glacier, i. 89, 94
McMurdo Sound, i. 41
Hill beds, Graham Land, i. 314
Island. i 301, 311, 313, 317, 318
inland, structure of, i. 61
origin of, i. 16
pie-crust, i. 37
plateau, i. 19, 26
recrystallisation of, ii. 10
rippled, between layers of ice, i. 168
supply, i. 25, 27-31
tabloids, i. 89, 156, 164, 168
trees, i. 41
Valley, i. 98
Snowfall, i. 14, 15, 25, 27-31
C. Royds, i. 17, 31, 32, 34, 102, 180
Scott’s Depot A, i. 32
Granite Harbour, i. 30
Great Ice Barrier, i. 31, 32
266
Snowfall—continued
King Edward VII Plateau, i. 29
Magnetic Pole Plateau, i. 25, 26, 28. 29
South Pole. i. 29
Western Mountains, i. 31
Snowfields, inland, i. 61
Magnetic Pole Plateau, i. 60
Soda-hornblende, i. 246
Soda-orthoclase, ii. 109
Soda-pyroxene, i. 246
salts, i. 148; ii. 216
Soda-sanidine, i. 257; ii. 96, 120
Sodalite, Mt. Cis, i. 257; ii. 94, 97, 99, 104, 114, 171
Sodalite-syenite, i. 110, 244
Soils, 1. 89
chemical decomposition, ii. 89
experiments on the growth of wheat, ii. 89
report on, chemical analysis, ii. 91
comments, ii. 90
general nature, ii. 90
mechanical analysis, ii. 90
Solenopora, i. 234, 241, 315; ii. 82
Solfataras, Mt. Erebus, i. 212
Solitary Rocks, i. 87, 88, 90, 91, 92, 94, 206
Sollas, Professor, u. 145
Solvsbergite, C. Royds, i. 111; ii. 179
Soundings, i. 9, 11, 63
alongside iceberg, C. Royds, i. 132
G> Birds 1. 115
Crozier, i. 134
Royds, i. 109, 115
deepest off Ross Barrier, i. 136, 138
Drygalski Ice Barrier Tongue, i. 200
Geikie Inlet, i. 63
Glacier Tongue, i. 105, 106
Granite Harbour, i. 81, 115
McMurdo Sound, east side, i. 115
muds from, ii. 55
New Harbour, i. 115
North Sea, i. 146
off Ross Barrier, i. 123, 125, 127, 132, 134, 135, 138,
144
maximum, i. 134
Relief Inlet, i. 63
table of, ii. 55
South Africa, i. 6
African quartz-dolerite, i. 255, 291
America, i. 291, 295, 298, 299
trend lines, i. 317
Arm, i. 8, 86
Geographic Pole, i. 27
Georgia, i. 302, 305, 312, 317
Magnetic Pole area, i. 3, 22, 35, 114, 202, 292
Orkney Islands, i. 302, 305, 312, 317
temperature, i. 22
Pole, i. 2, 3, 14, 20, 22
plateau, i. 20
snowfall, i. 29
winter temperature, i. 20
Sandwich Islands, i. 297
Shetland Islands, i. 297, 302, 312, 317
INDEX
South Victoria Land, i. 2, 3, 6, 8, 11, 24, 98, 189, 190,
287, 298, 299, 305, 308, 309, 310,
317-19
effect of glaciers on Ross Barrier, i. 111
ice discharged from, i. 141
physiographic and tectonic features, i. 6,
200, 316, 317
pre-glacial history of, i. 291-96
terraces, i. 201
volcanic rocks, i. 303
Southern Brazil, i. 298, 313
Ocean, i. 27-30
Party, i. 118, 122, 127, 185, 234, 235
Patagonia, i. 314
Supporting Party, i. 185
Specific heat of basalt, 1. 18
granite, i. 17
ice, i. 18, 62
ice and rock, i. 19
sea-water, i. 18, 62
Speedwell Island, i. 298, 311
Sphene, i. 233, 246 ; ii. 143, 144, 161, 162, 166, 171, 176,
223, 224, 226
Sphene-bearing diorites, i. 55, 78, 80, 244, 246
gabbros, i. 245
granites, C. Irizar, i. 50, 66
Sphenopteris hymenophylloides, i. 313
williamsoni, i. 313
Spherulites, ii. 176
Spillway glaciers, i. 45, 57, 60, 87
Spillways, i. 5, 8, 57, 200
Spiracle-ice, i. 35, 36
Spirocyathide, i. 240, 315
Spitzbergen, i. 269, 275
Sponges, i. 230
Sponge, siliceous, Backstairs Passage, i, 266, 267,
275
Drygalski Barrier, i. 56
Glacier Tongue, i. 105
MeMurdo Sound, i. 230, 231
spicule ooze, i. 180, 230
spicules, Backstairs Passage, 1. 266
C. Barne, i. 274, 275
Glacier Tongue, i. 231
Heathcotian series, Victoria, i. 243
Hut Point, i. 274, 275
Lower Glacier Depot, i. 235; ii. 194
marine muds, ii. 55
Stranded Moraine, i. 243
Spores, Clear Lake, i. 156
Stachypteris, i. 312
Stalactites, ice, i. 183; i. 17, 18
Blacksand Beach, i. 178
Star-fish, i. 231
Staten Island, i. 300, 311, 312
Steffen, H., i. 299
Steinmann, G., i. 299
Steps, i. 200, 201
Stilbite, ii. 156, 178
Stillwell, F. L., B.Se., i. 196
Strahan, A., Dr., i. 296
INDEX
Stranded berg, C. Royds, i. 173, 174, 182, 183, 191
Moraines, i. 95, 199, 203, 233, 262
McMurdo Sound, i. 96, 97, 98
near C. Crozier, i. 133
Stratigraphical geology, i. 232
Striz, i. 66, 79, 82, 83, 109, 194
Stromboli eruptions, i. 215
Sub-Antarctic Islands, ii. 27
Sublimation, i. 193; i. 18
Submarine ridge between Granite Harbour and C. Bird,
i. 115, 116
off Ross Barrier, i. 144
ridges near 170° E. long., i. 302
Subsidence, Sunk Lake, i. 109, 139, 167
Suess, E., i. 297-300, 302, 305, 306, 309-12, 317-19
Suess Nunatak, 1. 81, 82, 201, 298
Suliman Mountains, i. 317
Sulphur, C. Barne, i. 219
Cones, i. 222
Mt. Erebus, i. 212, 213
Sulphuretted hydrogen, i. 153
Sunk Lake, i. 44, 102, 148, 166, 168, 169, 201
area, 1. 169
description of, i. 109
plan of, i. 167
prismatic ice, i. 169
subsidence, i. 139, 167
trend of axis, i. 109
Sweden, i. 255, 308
Swiss Alps, i. 19
Syenite, i. 110, 244, 308; ii. 142, 171, 172
Fiji, i. 307
Synclines, i. 5
Syringocnemide, i. 240
TACHYLITE, Ul. 107
Tahiti, i. 807
Tale, ii. 195
Talus scree, i. 88
Tardigrada, Clear Lake, i. 156
Tarns, i. 108, 147, 148, 151
Tarr Reiss 19
Tasman Sea, i. 318
Tasmania, i. 6, 319
Tasmanian dolerites, i. 256, 291, 308
permo-carboniferous, i. 298
Trias-Jura coal-measures, i. 255, 298
rocks, i. 250, 256, 291
Taxites tenerrimus, i. 313
Taylor, Griffith T., i. 8, 46, 87, 141, 200, 201, 234, 235,
243, 250, 293, 298, 315, 316
Taylor and Debenham’s Party, i. 30, 105
Teall, Dr. J. J. H., i. 312
Teall Nunatak, i. 48, 57
Te Anau fault, N.Z., i. 319
Tectonic geology, i. 297-319
structure of Antarctic, i. 299
Temperature, i. 14, 15, 19, 20, 22
Bay of Whales, i. 189
C. Adare, i. 15, 17
Royds, i. 186, 192
267
Temperature—continued
crevasse, White Island, i. 125, 126
diurnal ranges of, i. 202
Drygalski Ice Barrier, i. 18
Piedmont, i. 187, 188
Farthest South journey, i. 16
Great Ice Barrier, i. 40
Hut Point, i. 15, 16
King Edward VII Plateau, i. 19
lake water, i. 169
Magnetic Pole area, 1. 16, 17, 18, 40, 41
Mt. Erebus, i. 16, 17, 18
Northern Hemisphere, i. 20, 22
plateau, i. 62
Pole, i. 14, 20, 21, 23, 27, 31
readings of Southern Party, i. 40
sea-water, Ross Barrier, i. 137, 138
Ross Sea and McMurdo Sound, i. 188, 189
serial, Ross Barrier, i. 145
Shetland Islands, i. 22
South Orkney Islands, i, 22
Pole, i. 22
Southern Hemisphere, i. 20, 22
Temperatures in lake trenches, i. 151, 153, 154, 156, 157,
162, 164, 165
taken by Nimrod, i. 17
water, Drygalski Piedmont, i. 188
Winter Quarters, C. Royds, i. 15, 16, 17, 18, 20
Teneriffe, i. 210
Tent Island, i. 225, 259
height of, i. 289
Tephrites, i. 257, 259, 309
Terra Nova, i. 11, 130, 136, 144, 317
Terra Nova Bay, i. 46, 48, 56, 62, 201
Terrace Lake, i. 148, 166, 167, 168, 229
algze, i. 168
trend of axis, i. 109
Terraces, i. 119, 200
“ alb,” i. 120
Backdoor Bay, i. 114, 201, 207
Beardmore Glacier, i. 119, 120
Blue Lake, i. 112, 157
GC. Bernacchi, i. 84, 85
Bird, i. 114, 201 207
Royds, i. 110
Clear Lake, i. 155
coast of Victoria Land, i. 201
Dunlop Island, i. 84
Mackay Glacier, i. 81, 82
Mt. Crummer, i. 201
Erebus, i. 44, 110, 111
rock, i. 69
Ross Island, i. 102
Terrace Lake, i. 168
Terracotta Mountain, i. 197
Terre Charcot, i. 317
Falliéres, i. 2, 317
Loubet Bay, i. 2, 317
Louis Philippe, i. 2, 303, 304, 311, 312, 317
Tertiary, i. 313
basalts, Tasmania, i. 256
268
Tertiary—continued
marine beds, i. 311
rocks, i. 301, 309, 316
Tetractinellia, i, 274
Thalway, i. 8
Thaw effect, algze, i. 147
Beardmore Glacier, i. 116
Blacksand Beach, i. 179
Blue Lake, i. 159, 161, 203, 204
Butter Point, i. 99
C. Armitage, i. 184
Royds, i. 110, 148, 202, 203, 204, 263
Clear Lake, i. 155, 203, 204
Coast Lake, i. 162, 203, 204
Crater Hill, i. 223
Drygalski-Nansen region, i. 204
Drygalski-Reeves Piedmont, i. 204, 205, 206
Dry Valley, i. 95, 96
Ferrar Glacier, i. 89, 90, 91, 92, 93, 94, 155, 203
Glacier Tongue, i. 103
icebergs, i. 172
ice foot, i. 176, 179
Larsen Glacier, i. 204, 205, 206
McMurdo Sound, i. 190
Mt. Erebus, i. 118, 210
Penguin Rookery, i. 191
Ross Barrier, i. 117, 118, 136, 144
Sea, eastern side, i. 189
sea-ice, i. 187, 188, 190, 193
Skuary, i. 107, 108, 228
Stranded Moraines, i. 96, 97, 98
Tent Island, i. 225
Wilson Piedmont, i. 100
Thermometers used on Magnetic Plateau, i. 18
Thinnfeldia, i. 313
indica, i. 313
Thio-bacteria, ii. 5
Thomson, Allen J., i. 221, 291, 307; ii. 94, 119, 131
Thracia meridionalis, i. 266, 314
Tidal movement, Ross Sea and McMurdo Sound, i. 187
Tide Crack, C. Armitage, i. 185
Barne, i. 108
Royds, i. 173, 176, 179, 180, 184
Glacier Tongue, i. 105
Great Ice Barrier, i. 116
Green Lake, i. 149
Tierra del Fuego, i. 297, 302, 304, 311, 317
Till, i. 9, 100, 265
Tillites, India and Australia, i. 196
Timber, dry distillation of, i, 281, 282
Tind, i. 69
Titaniferous iron, C. Royds, i. 111, 246
pyroxene, ii. 104. 108, 109, 113, 116, 125
Titanium, i. 246
Todites williamsoni, i. 312
Tonga Kermadec Deep, i. 306
Tongan Deep, i. 318
group, i. 302
Tourmaline, ii. 231
schists, C. Bernacchi, i. 233, 234, 247
Trachydolerites, i. 114, 224, 257, 258, 260, 309; ii. 109
INDEX
Trachyte, i. 309; ii. 102, 119; see Petrological
descriptions
Auckland, i. 306
Blue Lake, i. 161
Campbell Islands, i. 306
C. Barne, i. 167
Bird, i. 114, 218, 260
Clear Lake, i. 112
Dunedin, i. 306
Tnaccessible Island, i. 224; ii. 102
Mt. Cis, 1. 257; 1.99
Erebus, i. 111, 257; ii. 94
Observation Hill, i. 222, 264; ii. 101
orthophyric, i. 308
Razor Back and Little Razor Back, i. 225
sapphire-bearing, C. Royds, i. 111; ii. 180
Skuary, i. 259
spherulitic, C. Royds, i. 111; ui. 182
Transportation, i. 206
Travertine, ii. 203
Treads, i. 200, 201
Tremolite, ii. 183, 185
Tremolite-schist, C. Royds, i. 111, 234
Trenches, Blue Lake, i. 159, 160, 161, 162
section of, i. 160, 162
thickness of ice, i, 159, 161, 162
Clear Lake, i. 155
thickness of ice, i. 155
Coast Lake, i. 162, 164, 165
Green Lake, i. 151-54
dimensions of, i. 152, 154
temperatures, i. 151, 153, 154
thickness of ice, i. 152, 154
Round Lake, i. 165
Trias-Jura, i. 313
coal-measures, i. 255, 298
rocks, Tasmania, i. 250, 256, 291
Triassic fauna and flora, i. 236
Tributary glaciers, i. 122
Triceratium, i. 230
Tridymite, ii. 145
Trilobites, Lower Glacier Depot, i. 235
Tripp Island, i. 77
Trogschulter, i. 82
Trogtal, i. 119, 120, 200
Trough faults, i. 5
Tuff, Buckley Island, i. 242
C. Barne, i. 219
Royds, i. 111
Cone, i. 221
erratics, i. 221
lava, i. 221
Dry Valley, i. 95, 223
East Fork, Ferrar Glacier, i. 94
Hut Point, i. 222
Tnaccessible Island, i. 224
Mt. Erebus slopes, i. 222
near Blue Lake, i. 112
Skuary, i. 107, 227, 228
Stranded Moraines, i. 87
Turk’s Head, i. 107, 226, 227
Tundra conditions at South Pole, i. 254, 255
Tunisian mountains, i. 317
Turk’s Head, i. 107, 224, 225, 226, 259
agglomerate, i. 226, 227
Glacier, description of, i. 106
iceberg, i. 106
ice cave, i. 106
source of supply, i. 106
Nunatak, i. 106, 225
Twin Peak, i. 158
UnNpDULATIONS in sea-ice, i. 184, 185
Upper-Cambrian, i. 243
Upper-Cretaceous, i. 315
South Africa, i. 291
Upper-Devonian, i. 249
Upper-Eocene, i. 315
Upper Glacier Depot, i. 251
Upper-Gondwana, i. 313
Upper-Jurassic, South Africa, i, 291
Upper-Miocene, South America, i. 314
Upper-Oligocene, i. 313
Uralite, ii. 178, 227
porphyry, Depot Island, i. 246
Usnea, i. 229
VaLiey in Valley Structure, i. 119
Valleys, “ alb,” i. 200
alpina, i. 8
east and west, Ross Barrier, i. 127
glacier, i. 77, 82, 83, 200
Greenland type, i. 8, 201
hanging, i. 200
horst, i. 8, 64, 101
“ outlet’? type, i. 8, 201
overdeepened, i. 81, 82, 119
U-shaped, i. 82, 200
V-shaped, i. 119
Valvatella crebrilirulata, i. 266
Vancouver, i. 304
Variolitic basalt, i. 195
Vega I Islands, i. 318
Verkhoyansk, i. 14
Victoria Land; see South Victoria Land
quadrant, i. 1
Volcanic eruption, recent, i. 6
glass, i. 213, 226
ridge, C. Armytage to Glacier Tongue, i. 102
zones, i. 5, 208, 223, 301
Volcanism, i. 208
Voleanoes, Bridgman Island, i. 318
Deception Island, i. 318
height of, i. 223
South Victoria Land, i. 318
submerged, i. 9
Von Toll, i. 237, 240, 241
Vosgesite, C. Royds, i. 111; ii. 177
Waricatcu Island, i. 236, 315
Walkom, A. B., i. 234, 251; ii. 161, 206
INDEX 269
Wandel Island, i. 304
Water-bears, i. 156, 161
Water-blink, i. 189
Water-sky, McMurdo Sound, i. 190
Weathering, i. 66, 97, 193
changing temperatures, i. 193, 194
chemical, i. 198
concentric, i. 194
due to evaporation, i. 193
frost, i. 109, 194, 195, 199, 206, 207
kenyte, i. 195, 196, 226
Skuary, i. 107
sub-aerial, i. 196
Tuff Cone, i. 221
Turk’s Head, i. 226
wind, i. 195, 196, 197
Webb, E. N., i. 61, 202
Weddell quadrant, i. 1
Sea, i. 2, 12, 122, 189, 292, 318
Wehrli, L., i. 299
Wernerite, ii. 166
West Antarctica, i. 316, 317, 318
Western Greenland, i. 3
Inlet, i. 130, 131, 137
current meter, i. 145
Mountains, i. 6, 8, 9, 11, 12, 31
Party, i. 41, 87, 88, 95, 97, 155, 184, 191, 199, 203
White, Dr., i. 253, 313
White Island, i. 5, 125, 271, 272, 274, 287
Wickmann, A., i. 307
Wilckens, O., i. 299, 313, 314
Wild, Frank, i. 122, 235, 241, 248, 249, 252, 315; ii. 83
Wild Mountain, height, i. 122
Wild’s Store, ii. 19, 21
Williamsonia pecten, i. 313
Wilson, E. A., Dr., i. 99, 102, 110, 116, 234, 289, 315
Wilson Piedmont, i. 99, 100, 101
area and description, i. 100
origin of, 1. 100, 101
Winds, i. 12, 14, 18, 19, 20, 22, 29, 31, 40, 41, 42, 50, 51,
62, 90, 92, 95, 97, 108, 151, 187, 188, 196
anticyclonic, i. 28
Backdoor Bay, i. 191
Bay of Whales, i. 189
C. Royds, i. 180, 185
carrying rock material, i. 196, 197
circulation of, i. 18, 20, 22
cyclonic, i. 28, 29
Ferrar Glacier Valley, i. 197
Mt. Erebus, i. 213
Plateau, i. 189, 190
prevalent, i. 22, 23, 24, 25, 31
removal of snow, i. 202
Winter Quarters, C. Royds, i. 8, 15
Wohlerite, i. 244; ii. 111, 171
C. Royds, i. 110
Wollastonite, ii. 143, 144
Wood, fossil, i. 120, 121, 248, 249, 256
Woodward, A. S., Dr., i. 8, 243, 250, 298
Woolnough, W. G., Professor, i. 110, 234, 244, 245, 255,
260, 308; ii. 159, 169
270 INDEX
Wright, C. §., i. 145, 315 ZaGROS Hills, i. 317
Wright Glacier, i. 87 Zeuglodon, i. 314
Zerion, i. 245
Zircon, ii. 99, 105, 140, 162, 166, 174, 211, 224
XENOCRYSTS, ii, 144 Zirconia, ii. 111
Xenolith, ii. 144, 176 Zululand quartz-doierites, i. 308
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